unregistered will

The query is too speculative and suggests no legal elements or legal issues. Anyhow, it is not necessary that a Will be registered.

I have purchased(registered sale deed dec 2018) a 10 ac land from person who purchased it in 2015 from beneficiary of unregistered will(Dated oct 1986 from father who deceased dec 1986) and Had his name in ROR &1B . The will beneficiary have 2 sister (got married before 1985) who didn't got any benefits from will. Now I came know that B is in very difficult financial situation and he is not at all good person.Now my query is does he have any chance to make his sisters aware of their share in father property and make them to claim partition of property by chellanging unregistered will . 

*Is this useful for me:* The beneficiary made a sale deed for 6 cents of the same(survey no) property in 2001. Does this activity make adverse possession.and also made registered gift sattlment to his wife in 2006 for 2 ac.Is these two transaction in same survey number give adverse possession. 

sir is there any risk for my property...