Loved the story idea! It could be all the characters end mentally unstable, the story never gets peaks of happiness, it keeps getting worse and worse... and the characters finally learn how to live their destroyed lives! I'm now imagining a brownish green atmosphere, a destroyed house with a guy wearing a bloody shirt, lying on the floor and making bubbles with his own drool while the armless kid sitting next to him laughs hysterically when the bubbles pop. Now I'm studying a bit of anatomy for my drawings. After that I wanted to create a graphic novel. Maybe you can develop the story, or help with it! (Warning: an INTP "maybe we could" means "between tomorrow and 20 years from now").