The First Three Rules by Adrienne Wilder

Marshal Jon Foster lost his purpose and his sanity the day he saw the image of his dead brother. The distraction saved Jon’s life but cost the lives of innocent people including his best friend and partner. It was a price for survival Jon couldn’t live with and was sure he’d never understand.

Driven by grief and guilt he tried to escape his past by fleeing to a small town in the middle of nowhere. Only instead of peace, the memories festered.
Then the offer of a stick of gum from a stranger changes Jon’s life and puts him on a road out of the nightmare he’s trapped in.

Ellis Harper has lived the past twenty years isolated from the outside world and sole caretaker for his mentally disabled brother, Rudy. While Ellis loves his brother, he longs for a life he’ll never be able to have.
Shut away, his days consist of chores, endless cartoons, and games of Go Fish. A world that seemed to have no end until an innocent misunderstanding turns Ellis and his brother into a target for a town bully.
It’s a fight Ellis can never win on his own but thanks to a chance meeting with a stranger, he doesn’t have to.

What begins as a new journey in love for both men quickly unfolds into something neither of them could have ever imagined.