Keike, my DH is going through this atm: he's applying for other jobs and telling his company that. His pay review is this month - they screwed him over last year too, this year he's leaving if they don't magically improve now he's threatening them.

He needs to see if he can get that overtime paid and needs to start saying "no, I'm not paid to take that responsibility" - I know it isn't what he wants to do, but it is his mental wellbeing on the line here. If they won't pay him to do the extra, he shouldn't do it. They are taking advantage and now he's suffering.