Hi Mike and dad!

What you will be doing, if I read you correctly, is applying for SSDI/SSI because of a developmentally disabled adult child.
http://www.ssa.gov/d&s1.htm

There are many words to click on at that site, that will explain themselves and list the things you'll need to know and follow.

A clinical psychologist can administer IQ tests to determine actual mental age, and provide documentation for the Social Security Administration. Your medical doctor can also give reports of particular examinations, that will add to the disabilities regarding physical maturity/imaturity. http://www.ssa.gov/disability/profes...odListings.htm

Good wishes!