If your boss is regularly expecting you to do the work of two people and consistently work overtime to do so it doesn't sound like he is a good boss and looking out for you.
The fact that he works longer hours than anyone else isn't justification for this. As the company owner his decision to do so is an option he has chosen and the benefit he gets from do so greatly exceeds the benefits you get from doing so.
Even with two people the way the schedule ends up you still need overtime. The thing is, the boss can't just start turning down jobs because we lose staff, if we can't do it we won't have jobs. It's not because he's a dick and wants to work us to death, it's because in order to maintain his business he needs the revenue. If we start turning down jobs our customers will go elsewhere. We've already had a few of our big contracts get cancelled because we can't keep up. It's the way the business works.
You have to work around the schedules of other contractors and professions and if you don't well, your company doesn't get jobs. There's a lot of competition in the industry. He doesn't expect me to constantly work overtime, I won't be fired if I don't, i've been told any time I can't it's ok, i'm never told I have to. I either make the decision to do so myself so the next day will be easier or i'm asked if I can.
I've never gotten in trouble for saying no and there are days where we're slower and there's not much to do. We don't get shit for taking it easy on those days or when we're standing around chatting when we have nothing to do. I personally work as hard as I do because I know I capable of it and it'sy job. I'm being paid to get shit done, when i'm at work i do what i'm being paid to be there for.
I haven't always had to work by myself. There were others doing my job when I started, one became the manager and has pretty much forgotten how to do my job. The other one first got moved to a different position outside after months of not being able to learn this job, eventually he got fired for fucking around too much. I was by myself for a few months after that while they kept trying to hire people who would either stay or actually work when they showed up.
I ended up getting a friend of mine a job with me and she did well at it. She was here for a year and a half before she had to leave due to health and overwhelming life issues at the beginning of this year. Since then i've been alone we hired one guy a little while ago, turns out he was just interested in things like where the security cameras were, which doors get locked at night, how much everything was worth, needless to say he didn't last long. The guy working with me now's been here a few months, he tried a few of the other jobs in the shop but the other people that work here weren't big fans of his work so for the last couple weeks he's been helping me. He's been picking things up, but there's a lot to learn and it takes time which I have to find in between doing my job. It's the kind of thing where a tiny mistake can cost thousands of dollars.
It's just kind of how it is, i'm in a fabricators facebook group. The top complaints from just about everyone is the lack of quality employees. Finding people willing and able to learn as well as being willing to work is difficult.
I dunno, everyone I work with is pretty dedicated to the shop and everybody else there. We like doing a good job. We like knowing our work is respected and valued. People are happy with what we make and we do things other people can't do. It feels good working hard in a place like that.
If he has more work than people the options aren't to regularly expect your employees to work overtime or turn down work. The answer is to hire more people. After this many years in business the owner should have a handle on his turnover rate and should be staffing appropriately so that loss of an employee doesn't leave him severely understaffed for an extended period of time.
If those in your industry are finding it hard to attract quality employees then it is likely that your industry is not offering the proper compensation to attract those employees.
The fact that he works longer hours than anyone else isn't justification for this. As the company owner his decision to do so is an option he has chosen and the benefit he gets from do so greatly exceeds the benefits you get from doing so.