If your daughter and the "deadbeat" are not legally married it would be tax fraud for them to file a joint tax return. A joint tax return can only be filed by a legally married couple.
As for claiming them for 2021----it's tricky---you do not seem to know how much (if anything) your daughter earned in 2021, and the year is not over yet. She may have earned too much for you to claim her. And if she files her own tax return, as a parent she has the first right to claim her own children. You have not mentioned your daughter's age or whether she was a full-time student in 2021---and those two things are very important.
Get more information and post back when 2021 is actually over and you can find out how much your daughter earned in 2021.
IRS interview to help determine who can be claimed:
https://www.irs.gov/help/ita/who-can-i-claim-as-a-dependent
https://ttlc.intuit.com/questions/3113432-who-can-i-claim-as-my-dependent
WHO CAN I CLAIM AS A DEPENDENT?
You can claim a child, relative, friend, or fiancé (etc.) as a dependent on your 2020 taxes as long as they meet the following requirements:
Qualifying child
- They're related to you.
- They aren't claimed as a dependent by someone else.
- They're a U.S. citizen, resident alien, national, or a Canadian or Mexican resident.
- They aren’t filing a joint return with their spouse.
- They're under the age of 19 (or 24 for full-time students).
- No age limit for permanently and totally disabled children.
- They lived with you for more than half the year (exceptions apply).
- They didn't provide more than half of their own support for the year.
Qualifying relative
- They don't have to be related to you (despite the name).
- They aren't claimed as a dependent by someone else.
- They're a U.S. citizen, resident alien, national, or a Canadian or Mexican resident.
- They aren’t filing a joint return with their spouse.
- They lived with you the entire year (exceptions apply).
- They made less than $4,300 in 2020.
- You provided more than half of their financial support.
When you add someone as a dependent, we'll ask a series of questions to make sure you can claim them. There may be other tax benefits you can get when you claim a dependent.
Related Information:
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
