He needs to file for a modification. See Dads House link below
Yes.
Only if the child has a severe disability.
" ... if your child is 33 ...?" Yes. (There is no statute of limitations on collecting past-due support.)
Take all written proof (paystubs, etc.) to the Child Support Services agency collecting the payments, or to the court where the judgment for child support was made.
Your Social Security eligibility is not affected by your receipt of child support. One is for you; the other is for your child.
No, but the child is potentially eligible for RSDI payments based on his disabled father's eligibility, and these payments would count toward the father's child support obligation.
There is no statute of limitations on collecting past-due child support.
This can be the case yes depending on the disability, insurances etc.
It depends if the child is in the group home because CPS/DCFS/DSS has placed them there you still owe child support and they are entitled to intercept and utilize all SSDI payments.
Most jurisdictions separate child support matters from other civil suits. In any case, I suggest that you contact your State's child support agency. They have ways of collecting unpaid support.
There is no statute of limitations on collecting past-due child support.
Yes. Disability of any sort is not exempt from attachment for child support and/or child support arrearages.