I don't think you are being awful!! I think you are at the end of your rope!! It must be really hard for you guys when his mum is just letting the problem go on. You would think she would want to work with you to help her son. The only thing I can think of is some form of counselling for him as it sounds like the problem isn't a physical one but you would probably have to convince his mum to be into it too. Good Luck - I hope things improve soon!!