Neighborhood kid , bad influence , comes over all the time - what do I do?

Hi,So this kid lives two doors down. My son is 5, he is 7. This kid is the child of a drug addict who does not have a father in the picture. His grand parents are raising him as she is in rehab very often. Whenever the mom is around we see her running up the street with her phone in her hand, I assume she is trying to score drugs.I don’t let my son into his house cause who knows what’s in there - the mother is a heroin addict.But the grand parents let this kid roam free all the time and he is always screaming and running down the street, ringing my doorbell when my 2 year old is sleeping. This kid almost always hurts my son - like 10 minutes ago he drenched him with the hose.My son is high functioning autism and obsesses over this kid.I had a period of time where I thought I’d be like a neighborhood dad to this kid , but he really is such an annoying kid- it broke my heart when I realized it - that I have to worry about mine and not him.Any advice on how to mitigate this is appreciated.Note: before anyone judges me for not welcoming this kid into my home, know that this has been going on for over 2.5 years and I’m just sick of it. He constantly throws our home into chaos and ruins a lot of god family time via /r/Parenting https://ift.tt/2moj1Bq