I'm not going to engage with this person anymore, for their own sake. I hope they get the help they need.

For anyone else reading this: if you have a loved one in your life that starts acting this way (unable to comprehend what people are saying, making connections to things that aren't there, having trouble distinguishing reality from their thoughts, etc), please try to get them some help. Schizophrenia and related ailments often don't appearing until a person is in their 20s, and they're no joke.