Is it to inform to a disputing wife about going abroad

Sir, We belong to Hindu Brahmin community. My husband and I are government employees. My son is software person working in Chennai. He married to a girl in April 2012. At the time of marriage, he was on site in London and she was working in Software industry in Hyderabad. Both of her parents are also employees. My daughter in law had quit her job for marriage and accompanied my son to London tow months after their marriage. We clearly told the other side before marriage itself that he went abroad for a short period only and would be back soon his project is completed. Accordingly he came back in November 2013 and started life in Chennei.. Since then the attitude of his wife and in-laws changed. They started down looking him.and the couple are now on their way to separation. She left him in June 2014 and came to her parents. From then onwards, she has been with them. In this process, she sent messages to my son that she would commit suicide and the like. We feel lucky enough that she did not do any such thing during her stay with my son. Now, he has again been sent to UK by his company. He went away without informing her. We are fearing to give his phone number in UK to them. Is this against law? The girl and her parents want divorce.