If you rather trust a private person than a custodianship court alone: Consider adult adoption.
It’s a completely new topic to me. I learnt that today from a terminally sick, very courageous last living parent to a disabled child and feel it’s crucial information.
If you want to help: Consider becoming a volunteer custodian or even adopt a disabled person under custodianship. Might even be an option when marriage is none for disabled partners? 🤔