Purchased land 32 years before, no mutation in 7/12 done.

My father purchased two plots of land 32 years before. My father is 100% blind, my grandfather has done everything at that time. but I think he had forgot to make mutation of 7/12. but he has two original documents, for first plot he has a sale deed (not on stamp paper) but having two small stamps stuck on first page and original signatures of seller and witnesses and his own. second plot, he has sale deed on stamp paper. Now my father has just retired he wishes to sell these plots. My questions are: what is the procedure of getting 7/12? we have only sale deed and nothing else (like no objection). some people said you will need no objection certificate from the seller, but sellers are dead. is sale deed is sufficient? we have paid property taxes. we have appointed an agent (employee of talathi office) for this. he took my father's thumb impressions on blank forms. he is saying talathi is asking for more money. they don't work without money. its been more than two months now. We have appointed him because he said you won't be able to get by your own, it is a very hectic procedure. Please help my father is 100 % blind.