How to Handle Accepting Payment from a Non-Guardian - ROI Needed?

A colleague and I are providing therapy to children in a family with divorced parents with split legal custody. When they began, a grandparent was paying for sessions so we had both parents sign a release to communicate about billing issues and send credit card receipts only. Eventually, Parent 1 (whose own parent was paying) revoked the authorization and Parent 2 began paying.

Parent 1 is currently in a voluntary treatment facility though this has no bearing on the legal custody. Parent 2 emails today saying there's a change in credit card, please coordinate with Grandparent. I respond that we will need a new release signed by both parents, as in the beginning; Parent 2 replies that isn't necessary since no information will be "released" and statements will still go only to parents.

However - the fact that a card is getting charged for the rendering of psychotherapy services seems like "information" being "released". (Plus the additional complication of Parent 1 specifically revoking the previous release of information.)

I can't find any good information to confirm or deny my understanding of this - thoughts?