If he registers with connextions you can claim child benefit for 6 months. The last post was right he cannot claim jobseekers unless he lives on his own, basically there is no help for the 16 to 18 year old who has left school doesn't want to go to college and can't get a job.
I have had 2 boys in the same situation, its all very well for people to say get a job, but it depends where you live. Mine took nearly a year each before they got jobs, they applied for everything. They kept at it and it paid off .