She does not need to file.
You do not report his/her income on your return. If it has to be reported,
at all, it goes on his own return. If your dependent child is under age 19 (or
under 24 if a full time student), he or she must file a tax return for 2018 if he
had any of the following:
1. Total income (wages,
salaries, taxable scholarship etc.) of more than $12,000 ($6350 in 2017).
2. Unearned income (interest,
dividends, capital gains) of more than $1050.
3. Unearned income over $350 and
gross income of more than $1050
4. Household employee income
(e.g. baby sitting, lawn mowing) over $2100 ($12.000 if under age 18)
5. Other self employment
income over $400, including box
7 of a 1099-MISC
Even if he had less, he is allowed to file if he
needs to get back income tax withholding. He cannot get back social security
or Medicare tax withholding.
In TurboTax, he indicates that somebody else
can claim him as a dependent, at the personal information section.
Note that social security benefits are not mentioned. Social security only becomes taxable
when added to sufficient other income. If she is otherwise required to file a tax
return, you do need to enter it in Turbotax (TT). TT will determine the taxable
portion.
Social security (including SSDI) becomes taxable when your income,
including 1/2 your social security, reaches:
Married Filing Jointly(MFJ): $32,000
Single or head of household: $25,000
Married Filing Separately and lived with your spouse at any
time during the tax year: $0
