I'd contact the school authorities and get them to get child services involved. He has to be going to school in the bad shape he is and they are authorities that the child welfare authorities are likely to listen to. Too, they can "nab" him when he's in school, get the woman out of the apartment, or lean on the landlord, etc.

If you want to be really "mean" you can call child services and threaten to take them to court for not responding directly; bet that will get a response!