What is the ruling on inheriting money stolen from the state, and is it permissible to perform Hajj from the profits obtained from it after it has been gifted and disposed of?

It is permissible for you to accept the land, invest in it, and benefit from what you earn from it, due to the permissibility of dealing with commingled wealth. You should advise your father of the necessity of repentance and returning the money he fraudulently acquired through forgery or similar means to his workplace, even if through indirect methods.