Money for benefit of son

Sorry, I don't think we can help with this. As far as your son, it sounds like he may have a representative payee who will "ok or deny" requests from you to use the funds for his benefit.

Per Social Security, the Administration will generally look to family or friends to serve as a representative payee, so it's a bit irregular if you, the mother, is not the representative payee.

Here are some links that may be of use:
http://www.ssa.gov/payee/faqrep.htm
http://www.ssa.gov/payee/faqbene.htm
http://www.ssa.gov/oig/hotline/repayee.htm