Are you asking if you can claim your son as a dependent? You say he is "in his 20's". If he is NOT a student and he had over $5050 of income in 2024 (not counting any Social Security) then he cannot be claimed as a dependent and has no effect on your tax return. If he cannot be claimed as your dependent then you are not able to file as Head of Household. You file Single.
IRS interview to help determine who can be claimed:
https://www.irs.gov/help/ita/who-can-i-claim-as-a-dependent
Am I Head of Household?
https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-filing-status/qualify-head-household...
If you qualify as Head of Household, when you enter your marital status (single or married filing separately) into MyInfo, and then enter your qualifying dependent, TurboTax will offer HOH as your filing status.
**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.**