Autistic children struggle with the concept that their loved ones can just cease to be. Chris even more so. It wasn't Bob's death that affected him more so than him losing what Bob provided, which was more freedom to spend his tugboat as he wanted.
With Barb, I feel like Chris will be more outwardly affected on an emotional level as this is the woman who was essentially responsible for how he turned out. Chris has relied on her coddling since the day she fired him out of her snatch and when she finally becomes worm food he will probably start having imagined conversations with a drawing of her Sonichu-self. I don't think it'll be to the extent where he just refuses to acknowledge her decomposing corpse in the room.
Then again I wouldn't put it past Chris to just buy an industrial size container of DampRid, leave it in whatever part of the hoard she's entombed in, turn on a shitty $30 WalMart air purifier, and hope Clover & Snoopy take care of the rest.