Myex husband co owns his business with his parents. His mother does all the bookkeeping as well as his taxes. He is nearly 30000 behind in payments. I understand they do not have to garnish his wages because he is not exactly on payroll being a part owner, but is there a way to go after the businesses profits?

You need to discuss this with your attorney or the agency that collects support. There may be ways to attach assets.

S corporations are required to file tax returns showing how much was distributed to each shareholder. And, in general, they are not allowed to accumulate earnings; they must pay the shareholders who are working for the corporation reasonable compensation. See this.

Garnish his earnings from the corporation and require the corporation to reveal his form K-1.