You don't include their income on your return. It would only go on their return if they are required to file one. If they only get ssi or SS, SSDI or a SSA-1099 they don't have to file a return and nobody reports it.
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-dependent/00/26111
Online is only good for 1 return per account. But you can use the same email address for 5 accounts. How to start another return in the Online version
https://ttlc.intuit.com/community/using-turbotax/help/how-do-i-start-another-return-in-turbotax-online/00/25596
Or go to the IRS Free File programs
Free File: Do your Federal Taxes for Free | Internal Revenue Service