Since you disclosed your plans of shutting down his internet and his phone last week, has he done anything differently? Has he made an effort to contribute to the household by securing his own phone or food stamps? (He is quite capable of finding this information on line, you know this).
if he is declared on disability can you cover him as a dependent on both taxes and your health insurance? (along with the monthly stipend you might get for supporting him)?
just questions to consider. although he graduated schools with no issue, there has to be some sort of testing.