To me, the conversation sounded more like an open dialogue. They were talking about personal stuff, and then he asked a question openly. I've outright asked people if they were feeling suicidal or if they were self-harming and then said based on how they were behaving, it had made me wonder. Those weren't judgements, they were observations and sometimes it's helpful when someone else points it out.

She didn't have to confess, although self-disclosure (at least for me) is way more likely when I'm in an up.

It sounds like he was being honest - by asking instead of just assuming. How does that make him into someone who's holding himself above another person?