I would say "don't think he wants to do it" is more precisely "don't think he thinks he can do it". Speaking with those in charities helping the long term unemployed, I've heard the "I won't be able to/can't do this" phrase much more than "I don't want to do it". It seems to be more about self-belief and confidence than motivation. After all, no-one wants to be poorer than the norm and without work.
