could be frand. Don't do it.

I work in mortgage bank. It could be a fraud case. And you are involved. Buyer don't have credit to get enough loan, so they take the money from you, if they can't flip the house to get profit, they could default the loan, leave the bank with a loss. So bank will take back the property, with inflated price. Bank could suit that guy, and you together, to get their money back.