Who paid for over half of the son's support?
Depending on the circumstances, the parents MIGHT be able to claim him as a Qualifying Child.
You'll need to determine if he meets the tax definition of "permanently and totally disabled" (see first link).
And $17,000 could be under the "substantial gainful activity" .
https://www.irs.gov/publications/p501#en_US_2024_publink1000220897
https://www.ssa.gov/oact/cola/sga.html
