Should I report my own son for elder abuse?

I assume that you know for sure that he is doing this to your parents. It sounds like he may have a drug addiction and need treatment. If he has already been in trouble with the law does he have a parole or probation officer you can report his actions to? Or does he have a doctor or counselor of some sort that you could talk to? You didn't say he is providing care for them, just living there. The immediate fallout from reporting his actions to an authority will be unpleasant for everyone, but how will it go over if he drains their funds and also dies from an overdose in front of them. That would probably be worse than trying to protect them now and trying to get him some help. For yourself, find a support group for family members of something like Narcotics Anonymous (NA). I say take action