Is it bad that I find the whole thing...kind of bittersweet? Like, this guy is balls to the wall crazy and totally incapable of dealing with other human beings, but he's also legit in love with the stupid pony plushie. He's been with it for longer than a lot of functional human relationships have lasted and he's happy to go places with it and order pizza with it and share his train wreck of a life with it. From an outside perspective, it's horrifying to watch, but inside that little bubble of crazy? He found The One and is perfectly content in his cozy, domestic bubble of delusion.
He'll probably snap one day and try to kidnap a woman to serve as a basement surrogate for his and Twilight's hybrid baby, but until then...eh, I guess there are worse ways to fly completely off the rails?