Property of ancestors with father in law needs to saved from selling.

I am a hindu girl married 3 years now. My husband is a native of madurai and the house they lived in is from ancestors. My in laws don't have a source of income other than from that. But the problem is they neither develop that nor maintain it. They force my husband to sign the papers to sell it. But we both don't have the intention to. What sort of rights do we have. The property belongs to my father in law by papers. Do we still have a hold on it. I was working before kid. But they forcefully stopped me continuing which drastically laid down our financial status. And what can I do to get a part of the income so that I can save it which is going to financially support us to grow our kid.