Parent did not mention the word depression, so I do not want to comment on their story, but I want to comment that major depression does have well documented symptoms of transient mental state where delusions and hallucinations feeds into depression. If I remember right from Robert Sapolsky, the mind is creating a plausible explanation for its current state, which is a thing the mind actually does for everyone, but with major depression it becomes quite extreme. It is not something a person can "snapp out" of or be talked into to see things rational. Robert Sapolsky see depression as mostly a biological condition with biological causes, and a common quote from his is that we don't tell people with diabetes to just get over it and start producing insulin.