As long as he meets all the qualifications. Take a close look at last three.
You can claim a child, relative, friend, or fiance (etc.) as a
dependent on your 2018 taxes as long as they meet the following
requirements:
Qualifying child
- They are related to you.
- They aren't claimed as a dependent by someone else.
- They are a U.S. citizen, resident alien, national, or a Canadian or Mexican resident.
- They aren’t 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).
- They didn't provide more than half of their own support for the year
