If he is going back to China, it is difficult to get child suppo

I would think you guys should sign an agreement on how much child support he should pay every month. (But do not count on it.) So you can always be able to get the money if he becomes rich. (If he is rich, he may be willing to pay the child support anyway.)

I have no experience and am not a lawyer. However, I feel, even if you get a good lawyer, it is difficult to get more than 75% asset, just because he might not pay child support. (He can agrees to pay, then go back to China.) Still, no harm to talk to a lawyer. (Big company normally has free legal consoling.)