From what you mention, it sounds like his behaviour has drastically changed. Have you considered the possibility that he is having serious trouble in his perso

From what you mention, it sounds like his behaviour has drastically changed. Have you considered the possibility that he is having serious trouble in his personal life - perhaps financial or relationship trouble? His recent behaviour does sound dodgy but in common with how people react when they are facing serious personal issues. It could also be that someone else is putting pressure on him in regards to this deal. You may want to approach him sympathetically to see if that could be the case.