Your DD can Complete the CSS Waiver Request for Non Custodial Parent form for each school that requires the CSS PROFILE. It would be up to each school as to whether they will grant the request.
I agree with others who have opined that getting child support, though not sufficient, will likely be considered as contact. That he refuses to complete the PROFILE form is not going to matter in that regard. Sadly, there are a lot of such situations.
As others have suggested, you may want to explain to your son what the situation is, and make sure that a lot of FAFSA only schools on the list. Bear in mind that the child support you get is included in your income on the FAFSA .
What schools does your son have in mind?