What kind of income did he have? Online is only good for one return per account. You can use the same email address for 5 accounts. They can probably use the Free Edition. How to start a new online return
https://ttlc.intuit.com/community/using-turbotax/help/how-do-i-start-another-return-in-turbotax-onli...
You can still claim them on your return. Be sure on their return they check the box that says they can be claimed on someone else’s return. If their only income is W2 and under 13,850 they do not have to file a return except to get back any withholding taken out.
Filing requirements for a dependent
https://ttlc.intuit.com/community/children-dependents/help/do-i-need-to-file-my-own-taxes-if-i-m-a-d...
I think since he is underage he will have to print and mail the return and then you can sign it.
