Buying a house from father-in-law - how realistic?

Hello friends of finance, my wife and I are currently in a situation in which we could buy the house from my father-in-law (hereinafter SV) for €320k. The house itself is actually perfect for us; My wife's grandfather built it in the 70s, then passed it on to his son, but he wants to sell the house to us. I'm relatively neutral about the whole thing because, let's put it this way, my father-in-law isn't exactly the most generous person