I think if you want to wait for him then do that you really have nothing to lose but don't find yourself waiting forever. Allow him to take care of his mother and get through final exams but you can keep in contact through emails and phone calls if possible just to see how he is doing and show him that you support him. In time he may come around and realize that he wants more than just taking care of his mother and school but you have to appreciate a man that puts his mother first that show that he would take good care of the person he loved, how they treat their mother is a tell tale sign of how they would treat you. You are going to have to give him some time but wait as long as you are willing to wait. I think it is a very good chance that the two of you will meet in the future like the saying goes "You never know what the future holds" so keep the faith and at least try to stay in his life even if only as a friend right now at least you will still have him in your life.
I understand what you are saying but the truth is that I barely know this guy and don't think I could be his friend. I would be professional with any work dealings with him but beyond that he might think that she is been nice possibly to get with me so the friiendship thing might be a bit much. If I were to be his friend I know myself and I could start thinking that this could lead to a realationship and I don't ever want to face that disappointment ever again.
Thanks for your advice though.