in case the land is still in grand father s name, then how your uncle got it transferred/registered in his name. if you in possession, you may seek restraint orders from the appropriate court and also seek cancellation of registered document in favour of uncle.

confusion in question

Your question itself is contradictory and confusing to get a legal opinion. On the one hand your grand father registered the property in your mom's name and on the other hand your uncle got the same in his name through forgery and lastly the property is still in your grand fathers name . Now tell me what is true.