If you provide more than 50% of your son's report, then he is still a dependent. You are correct, in general, college students without significant earned income are not included in the stimulus payments.
Your 529 plan fund distributed to your son, the beneficiary, in your son's name, are still coming from your plan. See: What does "financially support another person" mean?
Click the link for more guidance for entering: Form 1099-Q. and Form 1098-T.
@madmanc20
