'Course the wisdom of trusting that the guy who promised you the bonus and couldn't manage it, can actually keep the company going for five years is open to question. And even if he does, he still owes you that bonus.
Anyway, a bonus based on revenue's a lot like my income tax (and the OP's boss's, I'll bet): I better hang onto enough to pay it—if that isn't deducted at source—at the end of the year, no matter what my high expenses, low revenue and hard times. Not complicated. All you gotta do is remember, that money's spent, and no longer belongs to you. 'Cause the deal w/ the CCRA is: You pay what you owe. And—as in your example—CCRA's happy to keep me working and arrange terms, rather than jail me and get zip. But they don't forgive the debt just because I pay on time from here on.
My bet is if the boss had cried poor and asked for understanding from his employees, they might well have cut him slack and not rushed off to the authorities. But apparently he thought he could do what he wanted. When the employer put the bonus in the contract, it stopped being a matter he got to decide all alone. He owes what he owes.
If he's too dumb to put aside the promised percentage as it came in or to talk to his employees, his future's likely short.