technically speaking, you can in fact gain mental disorder traits from spending too much time with someone who has a mental disorder. I once read an article about a woman who was a prostitute for a mexican cartel, who spent so much time around murderers and psychos that eventually she herself got completely ****ed up and career changed into a hitwoman with a grotesque gore fetish (as in, when she started she was horrified by all the death in their wake, but by the end, she would do weird things with the corpses of her victims). it is for this reason i don't suggest any of us spend too much time hanging out with an active serial killer.
practically speaking, unless this dude spent years as her sidekick I highly doubt that's what happened here
to be fair, most of those disorders are treatable