Perhaps it should be pointed out that the concessions not to fast when one is traveling allows a person to choose whether to fast or not to fast. It is authentically reported that the Prophet traveled with a number of his companions in Ramadhan. Some of them continued to fast while others availed themselves of the concession and did not fast. Neither group reproached the other for its choice. If you feel like fasting on such a journey and you are confident that fasting will not impose a too heavy burden on you, you may go on and fast. If you choose to avail yourself of the concession, you are perfectly entitled to do so.

2. Differences occur in the beginning and ending of Ramadhan, as indeed with every lunar month. Generally speaking, a lunar month starts when the new moon has been sighted. A new moon can only be sighted if it happens to be in the sky for at least a few minutes after the sun has set. The longer it stays, the greater the chance of it being sighted because the increased darkness makes it more visible. The new moon cannot be sighted on the same night throughout the world, due to differences in timings and geographical locations. But it should be possible to sight it anywhere in the world within a period of twenty-four hours. Therefore, differences of one day in the beginning of the month of Ramadhan, or indeed the beginning of any lunar month, are acceptable. When the differences run into two days, and sometimes into three days as happens from time to time, then there are mistakes in sighting the new moon. If one country starts Ramadhan two days before another, then one of them has started a day too early, or the other has started a day too late. Such mistakes do not affect the validity of fasting, because God accepts the action of any community in such matters as correct, provided that the community has taken the necessary steps to confirm the sighting of the new moon.

Nowadays, with the advances that have been achieved in astronomy and other fields of science, it is possible to calculate the possibility of sighting the new moon anywhere in the world well in advance. Therefore, a combined procedure of sighting the new moon with the naked eye and benefiting by such calculations should be adopted in order to make absolutely certain that the moon is sighted when it is born. This will preclude any possibility of mistakes.

Be that as it may, the fact that there continues to be differences of two or three days between two different countries in beginning the month of Ramadhan and ending it creates problems for people who travel in Ramadhan from one country to another. When a person encounters such a difficulty, he should try to make sure which sighting of the moon is more accurate. Suppose that a person started Ramadhan in a country which relies only on sighting the moon with the naked eye and pays no attention to the scientific calculation of the birth of the new moon. He then travels to a country which makes use of such scientific calculation and discovers that Ramadhan there started two days later. When he has completed thirty days of fasting, there is still one more day of Ramadhan in the country where he happens to be. Since this country takes both methods into consideration, then its timings are more accurate. Therefore, he follows the country which takes both methods and the fact that he completes his fasting into thirty one days means he had one extra day of voluntary fasting.

3. On the other hand, if his travel means that he has fasted only twenty-eight days when the Eid is celebrated in the country where he is finishing his Ramadhan, then he ends his fasting with the people of that country. He makes up by fasting another day later. That day may be the second day of Eid if he chooses, or he may leave it until later.

A miswak is a short stick which is taken from the branches of a particular tree, known as 'araak'. When the outer skin is removed it can be used as a toothbrush. Normally it is used without any toothpaste. It apparently has good cleansing effects on the teeth. The use of such a miswak is recommended during ablution and before prayer.

To use a miswak or a toothbrush when one is fasting is permissible. However, when one uses toothpaste, one puts oneself unnecessarily in a position which could spoil one's fasting. When one rinses his mouth, he needs to do that thoroughly, not as he does normally in ablution. Therefore, there is really a danger of swallowing something involuntarily. That is enough to render his fasting invalid for the day. From another point of view, it is discouraged to use a miswak or toothbrush after midday on any fasting day. The Prophet mentions that the smell of the mouth of a person who is fasting is "better, in Allah's view, than the smell of musk." When he uses a miswak or a toothbrush, he spoils that smell. This is the reason why it is discouraged. But it does not invalidate his fasting if he does not swallow anything of the water with which he rinses his mouth or washes out the toothpaste.

What is a father's responsibility when his children are grown up? Should he punish them if they are negligent of their Islamic duties? If he does, what would be the family situation like if the son replies in kind and gives his father a beating? Islam recognizes this possibility and, therefore, does not impose on a parent more than what he can do without difficulty. Moreover, the principle of individual responsibility is central to Islamic thinking. When a person is required to fulfill certain duties, they are required of him alone. Nobody else is questionable about the fulfillment of his duties. It is not right that a father should agonize and worry if his son fails to attend to his Islamic duties. What he should do is to remind him of his duty now and then, in the best way which he thinks would bring the son around to see the importance of attending to his worship. Allah says in the Qur'an: "Bid members of your household to pray and persevere in that." So, what a man is required to do is to bid his family to do their duties. If they do not do as they are bid, he is not accountable for their failure.

Let me now move to another aspect of your question, namely, the treatment of parents by their children. It is well-known that Islam requires every son and daughter to be dutiful to their parents, extending to them the kindest treatment possible. If a son fails to treat his parents kindly, he is guilty of disobedience to them as well as to Allah. There are several references in the Qur'an to kindness to parents as one of the most important duties of Islam. Indeed, failure to be dutiful to one's parents may deprive a person of his chance to be admitted into heaven. We note that, in several references in the Qur'an, dutifulness to parents is placed next to believing in the Oneness of Allah as a universal duty. A Muslim is not allowed to utter any word of annoyance to his parents or to speak harshly to them. If a son hits his father or mother, he may not be forgiven by Allah unless his abused parent forgives him first.

Having said that, I will now turn to your specific question. Let me say first that I am not in a position to advise you on the practical scope which you should or should not take. I do not know enough about your family situation to even start thinking of practical steps. What I can tell you is that if you can kick your sons out of your house in punishment for what they have done to their mother, you are, theoretically speaking, fully entitled to do so. You have done your duty by them, and brought them up to a stage where they can rely on themselves for their living. If you keep them in your house, on the other hand, you are not disobedient to Allah. Therefore, it is only you who can decide what is the best measure to be taken.

May I say, however, that your family circumstances are not ideal. You have been living away from home for nine years, leaving your wife to bring up four sons on her own at a stage when they are becoming young men. She might have been totally ill-equipped for the task. It is indeed a task that requires close cooperation between both parents. You speak of giving your sons strict orders to read the books you have left them so as to enrich their Islamic education. You have been sending them cuttings and passages of the Qur'an. But you do not know whether they have complied with your orders or not. Indeed, the very thought of giving such strict orders at a distance and expecting your sons to follow these orders with diligence is rather naive. How can you expect that the temperament of youth could be restrained by a far away father who gives orders which may not seem to the recipients even remotely relevant. When you have sent your children these orders and bought them these books, you might have thought that you have done all you can to bring them up as good Muslims. You should have thought better and realized that bringing up young men requires much more than that.