Karenmac has a point, last year I moved from one housing authority to the other as I have had health problems (depression) and I was classed as vulnerable, being kicked out by my exes house with our 2 year old. Because I had family in the area already and a support network they agreed, maybe you could bring this up with someone as he sounds pretty vulnerable. You could also try the CAB, or
http://www.connexions-direct.com/ and ask tghem if they know how he could get help. Surely even if he moves into a bedsit for a while until he gets sorted, it will be better than the alternative.
Wish you all the best of luck, let us know how it goes :)