I think many judges rule on child support according to the actual parenting time being exercised, not what is ordered. So if he is not exercising his parenting time, he will most likely not be awarded any parenting time adjustment. Is his parenting time overnight? If its not overnight, then many judges probably won't consider his parenting time anyway.
If you can prove that he has not exercised his ordered parenting time, I don't think you have much to worry about. Most judges I've encountered usually rule in mom's favor with regard to child support anyway.