Ration Card can be used deny rights to other tenent

Respected Sir/ Madam we are tenant of municipal corporation which was in my father name .We are three brother. My father expired in May 1997 . We gave share to elder brother and took notary undertaking from him that he has received his share and he would not make a claim to it in near future. and got the room tenancy transferred iln my mother name after taking NOC from all three brother [stating me and my immediate elder brother as nominee] and even electric bill was transferred in mother name . My elder brother took another room and his name was father name[expired] were deducted from ration card . and mother was stated as head. After few years my brother started a company and registered the company register office in above said premises. For which my mother said she had not given any consent this was in 2004. My mother expired in jan 2012. Tenancy is still in my mother name till date we have not transferred in any of our name.Current i and my brother reside in above said premises My Query 1] Can my brother proving the registered office of his company can deny me tenancy rights 2] can transfering the ration card in his name he can deny me tenancy right 3] can we have joint tenancy and how much does it protect my tenancy right 4] After being a joint tenant can i compel him to sell the above premise when i want to quit. 5] since development plan is around the local development group are approaching me to transfer the room in brother name and giving an agreement from brother that he will give me share of the room if development plan takes place . if the room is demolished in development plan .how much the legal document that assures me the share is valid. Please help