The "Champ's" answer is absolutely wrong. You can and should amend the return to remove your son. He can still go to https://www.freefilefillableforms.com/#/fd/economicimpactpayment and register as a non-filer and receive the full $1200 even though he did not earn any income for 2019. This is the alternative to filing a regular tax return in your son's case.
