Mevakesh1, I hear your pain, but you haven’t answered my question. Have you and your husband made an effort towards your brother-in-law?
There might be one of two things going on or both. He might be a very controlling person which is what you are afraid of. Or he might not feel that you have made any effort to be a family with him, just your sister and therefor he is only comfortable with his own family. After all, neither your sister nor he have a relationship with her parents so that is already one step removed, and if he doesn’t feel that you and your husband are making him feel warm and welcome into your very small circle, then don’t expect him to be the one making the effort. He is comfortable among his own and probably wants to give his wife a true sense of family.
Either way the question is what can YOU do to bring about a different outcome? If he refuses to make time to see you, then it would be up to YOU to make the time and effort to go see them. Maybe when he realizes that you are NOT a threat to his marriage or his other relationships things will slowly change. Maybe your husband can find himself in their neighborhood and stop by for dinner and to see the kids just to test the waters, etc. Usually, the men won’t see the other men in the family as a threat. Hatzlocha.