You do not need to do anything. He does not need to file since his total income is less than $1050. That income simply goes unreported.

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

**If his only income is from interest and dividends, Alaska PFD or capital gains distributions shown on a 1099-DIV, there is a provision for entering it on your return, using form 8814. Enter at Less common income / Child's income.