I couldn't reply to your first post but hopefully this post will allow a reply.
Much as I admire your spirit and determination I doubt anything you do will make the slightest difference, other than to mark your card.
Why don't you suggest to your mother that she appoints you as her enduring guardian with full plenary powers? That way you are in complete control in the future. All she has to do is say 'you must speak to my son who decides these matters'.
This is the WA version.
https://www.legalaid.wa.gov.au/find-legal-answers/managing-your-affairs/making-medical-decisions
