Should I claim supporting a person if they did not pay rent for 7 months?

In order to claim him as a dependent, he would have had to have lived with you for the entire year and earned less than $4,700 for the year.  If he earned more than that or did not live with you for the entire year, then you cannot  claim him for  the $500 Non-Refundable Other Dependent Credit

To claim someone as a Qualifying Relative, they must be:

• Your child ( including step children, adoptive children and foster children) or a descendent of them
• Your sibling (including half siblings) or a child of your sibling or a sibling-in-law
• Your parent or grandparents, including step parents and in laws
• Any other person that lived with you for the entire tax year
• Not a qualifying child of another taxpayer
• Someone that you provided over half of their support for during the tax year