1. You have no right on the property during the lifetime of your mother who was the absolute owner of her share of the said property,
2. Conduct a search from the local registration office to know what was the document through which the title of her share was conveyed to your cousin,
3. Contact a local lawyer to find out any flaw with the said conveyenca deed,
4. Verify whether the said deed was properly executed or not,
5. If any fault/flaw is detected, file a declaratory suit claiming that your mother's signature was fraudulently taken by your cousin,
6. However, your mother has to prove that she was defrauded by your cousin.