Panic like hell, but then I'd come to grips with my situation that this is sadly, my lot in life now.
But, I'd actually try to improve Chris' life from that point on. The hoard will go, and the room will be converted into something liveable.
Exercise would be a priority, as would fixing Chris' abysmal credit, both of which would take some time. I'd also see if I could improve his financial standing by working a 9-to-5 job and securing some form of savings plan for him, some of which would go towards him getting a proper degree. Chris would keep his hobbies, but I'd make sure he's not remembered for being a creep prone to emotional outbursts. I'll probably get him into the board gaming hobby, too.
After self-improvement (and seeing as how this was 15 years ago) I would try to get him into a stable relationship with Megan, providing that this isn't after he totally screwed up his chances with her by drawing that nude picture of her. However, it seems like there's a hint of her having taken advantage of Chris in the past (in terms of him buying stuff for her) so if things go that way, I either draw a line there or move on to somebody else. Everybody deserves some form of happiness, after all.
I don't know how I'd honestly cope with his parents, though. Bob seems fine, I might get along with him and may even get some respect out of him for actually making some effort to fix my life. As for Barb.....I really don't know. She seems like a really toxic bitch who would demand things be done her way and might actually stand in my way of getting that house clean (in terms of throwing out useless shit that can become a fire hazard.) Also, the creepy spooning thing. Eugh.
I'm fully aware that when that Freaky Friday thing comes to a close, it'd be undone, simply because Chris can't help being Chris.
But give me some points for trying here.