The tax laws apply to your child in this case, not you. Your child must answer "yes, I can be claimed as a dependent" on their tax return if they can be claimed, even if they don't want to be claimed, and even if there are other reasons why it would be better not to be claimed. Answering "no, I can't be claimed as a dependent" may, in some cases, constitute fraud.
There is no requirement that you actually claim your child on your tax return, only that your child must answer "yes, I can be claimed" on their tax return if they can be claimed.
What I don't know (because I have not studied the issue) is whether the trigger for disqualification from the student loan relief is the parent claiming the child, or the child being "claimable."
Depending on your child's financial and living arrangements, we could also discuss whether they qualify to be claimed in the first place, if you want to go down that road.
