The child did not live with you more than half the year and he probably provided more than half his own support for the year if he had a job living in another state for 7 months. Those are two reasons you could not claim him as your dependent.
There are two types of dependents--qualifying child and qualifying relative. Here is the list of requirements for qualifying child that must all be met:
1. The child must be your son, daughter, stepchild, foster child, brother, sister, half brother, half sister, stepbrother, stepsister, or a descendant of any of them.
2. The child must be (a) under age 19 at the end of the year, (b) under age 24 at the end of the year and a full-time student, or (c) any age and permanently and totally disabled.
3. The child must have lived with you for more than half of the year. Temporary absences while away at college are considered living with you.
4. The child must not have provided more than half of his or her own support for the year.
5. If the child meets the rules to be a qualifying child of more than one person, you must be the person entitled to claim the child as a qualifying child.
6. The child must be a U.S. citizen or U.S., Canada or Mexico resident for some portion of the year.
7. The child must be younger than you (or your spouse, if filing jointly) unless disabled.
The other dependent is qualifying relative and you can not claim him as a qualifying relative if he made more than $4200 in 2019.
