If my son's grandparent is claiming him, what do I check when it asks if the other parent is claiming him? Do I put no?

[xmasbaby0]

If your son's grandparent is claiming the child the child does not belong on your tax return at all.  The child cannot be on two tax returns.  That stuff about claiming the child as a non-dependent etc etc is only for two divorced or never married PARENTS who share custody.   You do not use that if a grandparent is claiming the child.  

[DavidD66]

You will be asked additional questions where you can indicate that another relative will be claiming your son.  When asked  "Who is planning to claim "your son" on their tax return this year?"  answer "I am".  On the next screen you will be asked "Did a relative of "your son's (other than you) live in your home for more than half of 2022 and help support Jimmy financially?"  Indicate "Yes".  Indicate who had the higher income, you or the grandparent.  Then indicate that your son's relative will be claiming him.  Answer to the above questions assumes that the grandparent lives in the same household, earns more than you, and will claim your son.