Big Stupid Jerk

No I am not talking about Bill!! I am talking about the homeowner of the house that we are about to buy, or should I say hoping to buy. Where to begin..........The jerk has been fixing the front wall termite issue. He now wants us to back out of the contract on the house because he thinks that since he has fixed things for us and spent alot of money that he could put the house back on the market and sell it for more. The whole front wall turned out to be infested pretty bad with termites. So he tore out the drywall to fix all of the framing, which was a total loss. Well he has decided that he has spent enough money, so he is NOT going to put drywall back up. So Bill said fine he would buy the drywall and fix it, that is when we found out that he was hoping we would back out of our contract. So when we move into our house in 2 weeks, when looking at our living room all you will see is 2 windows and 2x4 studs!! I have a really bad feeling. I think he is going to pull out of the contract and we are going to lose the house. Bill says that if he does back out, he is getting a lawyer and suing him for all the money we have spent!! I have been told that buying a house can be stressfull!! But come on, this is just STUPID!!