the earned income credit goes to the custodial parent based on their earned income, if they meet the qualifications. but you did bring up something in that he may have to file his own tax return and note on it they he can be claimed as a dependent.
filing is required if his unearned income is over $1100 for 2022
in addition there may be the "kiddie tax" if unearned income is over $2300
the kiddie tax applies when (certain rules have not been provided because they only apply if your son had earned income.)
1. The child had more than $2,300 of unearned income.
2. The child is required to file a tax return.
3. The child either:
a) Was under age 18 at the end of 2022 or,
b) Was a full-time student at least age 19 and under age 24 at the end of 2022.
4. At least one of the child's parents was alive at the end of 2022.
5. The child doesn’t file a joint return for 2022.
form 8615 is used and included with the son's return if subject to the tax
or since all the son's income is all unearned (assuming no withholding) she can include his income on her return (he doesn't file) by filing form 8814. the 8814 usually results in a higher tax because the first $1100 is taxed at 10% while on the 8615 it's taxed at zero.
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