If your son was incarcerated for most of 2019, you did not fully support him in 2019. He was supported by the penal institution where he was incarcerated at taxpayer expense. Spending money and incidentals you provided were not "support" as defined by the IRS. Money you gave to him during that time was a gift, which is not deductible.
Please use the IRS tool to see what the IRS says about claiming him:
IRS interview to help determine who can be claimed:
https://www.irs.gov/help/ita/who-can-i-claim-as-a-dependent
**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.**
