Yeah, there is no way they should be allowed to bill the estate which they themselves are administrating.
In a normal country with a social welfare program, the guardian would have to bill the government — if the government doesn't agree to lay down money to say that this person needs protecting, nobody gets paid.
(In an honest no-government-programs libertarian paradise like the US sometimes pretends to aspire to be, the guardian would have to bill some kind of health insurer that covered this specific care: and again, the insurer would take on the task of scrutinizing the claim.)
It is likely that the person in charge of quality of life and the person in charge of financial decisions should be different people, and somewhat adversarial. Neither should be paid directly out of the estate, and there would have to be a significant disincentive for any collusion between them that does not objectively benefit the ward.
In a normal country with a social welfare program, the guardian would have to bill the government — if the government doesn't agree to lay down money to say that this person needs protecting, nobody gets paid.
(In an honest no-government-programs libertarian paradise like the US sometimes pretends to aspire to be, the guardian would have to bill some kind of health insurer that covered this specific care: and again, the insurer would take on the task of scrutinizing the claim.)