I agree that now is the time for this child to be helped. I also agree that until his behaviors are addressed, you should take care around him.
I will gently point out though that assumptions and judgments are unhelpful here. I am terrible at writing anything negative or unsupportive, so forgive me if I don't get this right. But I just feel compelled to speak to a possibility on behalf of these parents.
From what you've written, it doesn't look like you are particularly close - either geographically or emotionally - to the parents or the child. So they may well be dealing with issues they haven't broadcast. They may be working hard with their child every single day on these behaviors.
They may be advised by professionals on discipline strategies that are outside the norm. They may have found (as I did) that public displays of discipline set their child back too much to justify them. So they may take their discipline into private (as I did), suffering the assumptions, judgment and derision of people around them, because it's what is best for their child. They may well be in a miserable, lonely place.
I agree very well put. When I struggle with issue with my children, while I do need to find people to talk with I try to find people who understand or are going through similar situations. I don't usually broadcast it to all my relatives or friends. I don't post on facebook about my son going to therapy, or that he was busy this summer getting testing. One year a relative heard through the grapevine that we were looking into ASD for DS and she sent me condolences. Really grated me the wrong way, particularly as it has been decided he isn't on the spectrum. And second because even if he was on the spectrum, it's not something that needs condolences. While this may or may not be what is going on here. I agree with the idea that it's possible he is getting help but you haven't heard about it.
