Sounds like you are trying to claim someone who was incarcerated as a dependent---which you cannot do. Any money you provided for someone's commissary account was a gift. Gifts are not deductible.
As for claiming an incarcerated dependent---you say it was for seven months. If you did not pay over half his support in 2020 he cannot be your dependent. His support was paid for by the institution in which he was housed for the seven months--and it is very expensive to incarcerate someone, so you did not pay over half. And a spouse cannot ever be claimed as a dependent.
If the incarcerated person is your spouse then are still allowed to file a joint return if you both agree to that. But the commissary expenses are irrelevant.
**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.**
