>We're together 5 years, married 1 year. I know I married a massive grump but with a kid on the way, I'm afraid he can't pull himself out of it on his own.

What you describe is way beyond someone being grumpy. And it isn't something you can fix.

He "felt slighted" waiting in line at a bar and "threw nasty slurs" under his breath, which they heard??

And "Everyone's an idiot out to get him"?????

I do not think books on stoicism are the answer.

>There are no therapy spots where we live and no online counseling.

Why is online counselling not an option?

ETA: In a comment you say you live in a "huge city" - there are no therapists there? (Or do you live in a place where therapy is not common?) In any case, online therapy is available from all over the world.