A family friend wants to sell their house, which we are in a position to buy for a fair price. It needs a lot of work doing to it, but the owner isn't in good physical health any more and wants to sell up so he can travel the world and has plans to move in with his long term girlfriend.

He is the sole owner of the property and has agreed to sell it to us slightly under market value as it requires a fair amount of modernisation (new kitchen, bathroom, rising damp, etc), but my MIL seems to think that his family can contest his decision to sell. I was under the impression that because he is of sound mind, and because he is the sole owner of the property he can sell it to whoever he likes for however much he likes. He's not leaving us the house in his will (which I believe could be contested). We would like to buy it from him.