my dh gets very worked up about work and i think this was one of the major triggers in the start of his severe depression.
i sometimes struggle with his obsession with work as to me a jobs a job and if you don't like the job/environment then get yourself another one! that's my very simplistic view and i've been lucky in my career that i've pretty much got the jobs i've wanted.
dh's depression, anxiety etc knocks his confidence and he becomes "fixed" and struggles to even submit CVs to agencies etc.
my advice would be to try and nip this in the bud, before it develops into anything more severe.
think getting signed off for a week or two is a great idea. even if the work "thing" isn't going to go away, your dh can use the time to review how he feels and what he wants and check out the market and see if there's any other opportunities etc.
this is a tough situation for you both and i do sympathise but if it's affecting your dh this badly, then it's not something he can tolerate so he needs to think seriously about leaving his employer.
my mantra to my dh is "priorities, priorities, priorities". unfortunately for him his shyster employer seems to win every time! and the really frustrating thing is that he's brillaint at his job and could walk into another one if he only believed in himself.
2 years ago he was a different man, full of self confidence and belief. his depression has eaten away at all that.
if we had recognised it earlier maybe things wouldn've have got as bad as they have.
sorry i've rambled on, really hope you guys sort this out and things improve.