If he was living independently, the minimum income required to file taxes is $12,950 in 2023.
But I suspect that he might qualify as a dependent on your tax return. I think you really needto find a sophisticated CPA to handle this correctly.
OR, let me give you one more great resource that could give you lots help. Go to
www.ProtectedTomorrows.com, where Mary Anne Ehlert has created an incredible resource for parents of special needs children.