My girlfriend and her grandson live with me. We are both 63, he is 12, i work and she is on ss and gets assistance. She claims she pays rent. My question is whether or not i can claim the child as a dependent and head of household? he has lived in myh.

Since the child is not your biological child or legal child by marriage, the child never qualifies you to file as head of household even if you can claim her as a dependent. 

You can claim her as a dependent if

• she lived in your home all year
• her taxable income is less than $4200
• you paid more than half her total support
• no one else claims her as a dependent. 
  
  
  

Thank you for the info, I wasn't sure about head of household but I will claim him as a dependent.