Absolutely! Your son can claim his son as a dependent as long as you are not claiming him yourself. He was in jail not prison correct? If he were to be in prison that is not the same and whoever took care of him would only be able to claim him. But 100% your son can claim his son. If you wanted to claim your grandson yourself since he was in your care while your son was in jail you would have that right. You would have to show records indicating he was in jail for most of the time. If you are all in agreement of who is going to claim him then it is no problem. I just got out of jail and have gone through the same thing. I was able to claim my girls for 2018 no problem.
