Foreigners married and moving abroad of Russian women often insist on taking their children with them, even if the child is not too small. This situation is normal, and I think we need to be ruthless to slow down. However, some women go further and try to take abroad by their mothers, brothers, sisters, aunts and even grandparents. I heard about a woman who tried to persuade her new husband to take her ex-husband with them, because his son has to miss him a lot. If you love this woman reason to satisfy such a request? 
As soon as you ask it concerns a distant relative, of course, he just wanted to make a profit you and I doubt anything that he thinks of you. However, if it was his mother, he wanted to return it, rather delicate matter.
The problem of relations between man and the laws of a wide spread in Russia. Russians are a lot of jokes on the subject. But what is the basis for the notorious conflict? This stubbornness of a spouse or a trick of his laws? This is not the first or second? In fact, the Russians are not currently practicing a close relationship between several generations of a dynasty make. A married woman who keeps contact with his mother, should be enough infantile. It does not make a good wife. He was not grown up enough to be his wife and prefers to play the helpless little daughter. Such a woman is unable to make decisions about themselves, and since then has been under the strong influence of his wife and mother. The case where there is even a small difference in their view, inevitably lead to serious disagreements. You should never agree to let her mother to intrude into your family life if it can easily turn into a battlefield. If your fiancee insists on taking his mother in another country, you'd better find another woman. However, you will be happy with my wife likes.