Apple can do more to support adults with intellectual disabilities!!!

I am the father of two Autistic young adults (aged 25 and 23). Their shared apple id is a part of my family sharing plan. They are smart enough to have figured out all the potential safeguards to prevent them from making purchases, and have made hundreds of dollars in unauthorized purchases (thankfully Apple has refunded most of them). This has caused me to not keep a valid payment method on file, preventing my valid recurring charges (e.g., Apple News, iCloud) from being paid.

Why doesn't Apple allow the organizers of family sharing plans, the right to prevent any member, regardless of age, from making purchases with the family plan organizer payment methods?

I can not tell you how frustrating and disappointing the lack of this feature is adversely impacting my ability to assist my disabled sons!! I have been a staunch buyer of iPhones and iPads since the beginning!!! However this issue is pushing me, and I'm sure many, many others, to a decision point.

Hopefully this will get the attention of Apple management and some sort of effective solution can be found.