Really anytime one person insists the other needs therapy or starts insisting they have a psychiatric diagnosis they’re probably an abuser. Calling someone a narcissist is one thing. Saying seriously that they have BPD, bipolar, are psychotic, etc without actual serious evidence is another. Pathologizing someone then insisting they need therapy to get fixed, and this person is required to make that fixing happen…
This happens to me all the time when I’m advocating for my rights as a disabled person. Other people get upset when I tell them they messed up. They tell me I need therapy, I guess to be less disabled or need less accommodations or not care when my physical needs aren’t met, unclear—and of course my actual existing mental health resources are apparently insufficient. I must have theirs.