Munchausen has its roots in wanting to be a caregiver. Chris is just a mentally stunted child copying a complete lunatic. He doesn't have a plan beyond attempting to latch onto the lifestyle and behavior of whoever he is in closest contact with. And Godbear help him, that just so happens to be Barbara Chandler.
That's not Munchausen, nor Munchausen by proxy. Munchausen syndrome is when a person feigns illness for sympathetic attention, Münchausen by proxy is when a caregiver deliberately harms or makes ill a person in their care so they garner sympathetic attention for being seen as a selfless caregiver.
It's like an autistic version of Munchausen Syndrome.
That made me grin, but I'm willing to wager there's an actual name for this behavior that isn't autism.