Hi, I did all this a few months ago. Once he's out call up the tax credits help line they will notify other agencies and if you're entitled to free school dinners, prescriptions etc they will let agencies know. You can go on line to the benefits checker now but until you are living apart you can't register for them. I left with my 3ds so my situation was different but the benefits checker is a brilliant tool. Good luck it's a very hard and lonely path to tread.