If your son is a qualifying relative then even it you don't claim him he still cannot claim himself.
WHO CAN I CLAIM AS A DEPENDENT?
You can claim a child, relative, friend, fiancé (etc.) as a dependent on your 2019 taxes as long as they meet the following requirements:
Qualifying child
- They are related to you.
- They cannot be claimed as a dependent by someone else.
- They are a U.S. citizen, resident alien, national, or a Canadian or Mexican resident.
- They are not filing a joint return with their spouse.
- They are under the age of 19 (or 24 for full-time students).
- No age limit for permanently and totally disabled children
- • They live with you for more than half the year (exceptions apply).
Qualifying relative
- They don't have to be related to you (despite the name).
- They cannot be claimed as a dependent by someone else.
- They are a U.S. citizen, resident alien, national, or a Canadian or Mexican resident.
- They are not filing a joint return with their spouse.
• They lived with you the entire year.
- They made less than $4300 (not counting Social Security)
- You provided more than half of their financial support. More info
When you add someone as a dependent, we'll ask a series of questions to make sure you can claim them.
Related Information:
• Does a dependent have to live with me?
• What does "financially support another person" mean?
• Can I claim a newborn baby?
