Maybe get some cheap help .

This is not OP's rsponsibility, his boss should do it. And IMHO if he (the boss) didn't in 6 years it's a clear sign that it's useless to keep trying to deal with this job.

The "blow it back" tactic can have a pretty useless result too: he (the OP) might even get a raise, but my experience tells me that the deadlines will continue to be tight and his stress won't fade away.

This is a matter of respect and minimum job conditions.