Them coming unannounced is exactly how it should work. You’re not a customer in that situation - you are the suspect. There are real problems out there. In this case it was suspicious that you might be one of them.

Your own child has a problem and you’re saying “we’ve had him evaluated” like they’re some malfunctioning animal. And then you’re calling his distress a “sob story”. Yikes! Obviously, I don’t know your real situation, but the way I understand it, presuming people are douchebags works when it comes to this social work stuff. Something strange happened and it would make sense that it would be recorded if other pathologies/patterns are detected later.