You need to remind him that if you work your ass off, you see no benefit if the company sells a few extra units.
My experience is that people who are truly financially vested in their own small company often have a hard time understanding that their employees can find jobs elsewhere if the company goes under. They cannot see beyond their own situation.
If you truly like working there and want to keep working there, then you'll probably need to roll up your sleeves and do what you can to make sure the company stays afloat. If it's just a job to you, remind him that there have been class action lawsuits recently over expected un-paid overtime where the employees have "won" (EA ring a bell). If he wants you to work extra hours, then he needs to pony up with either paid over time or additional vacation. It may take some numbers on your end to make him see your side. Let's say you have a salary of $52,000 ($25 an hour). If he expects you to work an additional 10 hours for free, your rate just dropped to $20 an hour. That's a 25% reduction.
Personally, I have left the companies where this has happened to me. They kept looking for ways to get "free labor" out of us, and I wouldn't take it.