Problems created by the in-laws of my younger brother

What can I do? My brother was residing in Mumbai. He lost his job and asked me to support him, his wife and 1.4year child. I wad forced to call him to Jamshedpur. He stayed in my home. Got 2 jobs but soon got kicked out. My parents came to visit us from bangalore. They advised him to come along to bangalore. He agreed. His wife was against. For few days they all resided with the relatives in Kharagpur. Some fight took place between him and his wife. Brother's inlaw got information some how. They came and took his wife to Jamshedpur. A meeting was later arranged. Matter was settled. That my brother would work here in Jamshedpur Until he gets the job he and his family would stay in my house. Then a bound was sent by his inlaws that if again any type of harassment is done to his wife then they are authorised to take action against me and my brother in court. Plus my heir and successors will also be bound by these terms. Why they are doing this? Please help!