1) un regsitered partition deed is in admissible in evidence
2) deed of partition appears to be under stamped too .
3) it is better your grand father / father file suit in court to set aside alleged partition as it has been executed under undue influence / fraud . . your grand father has no eye sight and was not aware of document signed by him . further your father is illierate
4) will takes effect only on death of testator ie grand father not during his lifetime
5) your uncle will challenge will on grounds that partition has already taken place although the said partition deed would not be admissible in evidence as it is understamped and not regd