it does work that way and emphatically NO, they will not ask for it back. LEgally, they can not ask for it back - it's not a 'probably not'.
the stimulus payments were 'advance payments' against 2020 tax return. Obviously, the IRS didn't know what would be on anyone's 2020 tax return when the 1st two stimulus payments occurred, so they used 2019 tax data (and in some cases 2018) to ESTIMATE what was due each person.
Then, then they are using the ACTUAL 2020 tax return data (income, dependents, etc.) to determine what you are ACTUALLY due.
if what you are ACTUALLY due exceeds what was ESTIMATED, the difference is posted on Line 30 and you get that as a credit.
if what was ESTIMATED exceeds what you are ACTUALLY due, you are not required to return it and that was specifically in the law Congress passed, Line 30 will be zero and can NEVER be negative.
If you read through what I wrote for your situation and then again for your son's situation, you'll see that you EACH are getting the stimulus / Recovery credit even though it appears your son is getting the money twice. But that is the way it works! Congress and the IRS knew it when they passed the law with these rules.
