Yes, you would claim him. If he qualifies, you can't not claim him to give him something he would not be entitled to.
If you are asking if claiming him will reduce his refund, it may or may not.
Dependents have a unique standard deduction. Dependents – If you can be claimed as a dependent by another taxpayer, your standard deduction for 2021 is limited to the greater of: (1) $1,100, or (2) your earned income plus $350 (but the total can't be more than the basic standard deduction for your filing status).
Qualifying child
In addition to the qualifications above, to claim an exemption for your child, you must be able to answer "yes" to all of the following questions.
- Are they related to you? The child can be your son, daughter, stepchild, eligible foster child, brother, sister, half brother, half-sister, stepbrother, stepsister, adopted child or an offspring of any of them.
- Do they meet the age requirement? Your child must be under age 19 or, if a full-time student, under age 24. There is no age limit if your child is permanently and totally disabled.
- Do they live with you? Your child must live with you for more than half the year, but several exceptions apply.
- Do you financially support them? Your child may have a job, but that job cannot provide more than half of her support.
- Are you the only person claiming them? This requirement commonly applies to children of divorced parents. Here you must use the “tie-breaker rules,” which are found in IRS Publication 501. These rules establish income, parentage, and residency requirements for claiming a child.
