You'll get good support and advice on the elderly parents board.
Unfortunately if a dementia sufferer is deemed as having capacity still, it can be tricky to get enough support unless something "really bad" happens, such as a fall requiring hospitalisation or a wandering episode involving the police.
If the relative has carers coming in, I assume that ASC has been involved, unless it's all self-funded and through a private agency.
A situation like this should fall under safeguarding, but alot hinges on how the dementia sufferer presents to the professionals they encounter, and some can "show time" or "hostess mode" very convincingly.
Does the daughter have POA?
Unfortunately someone deemed to have capacity has the right to make unwise decisions, and it can be a bit of a minefield. They also retain the right to make decisions around their care, where they live etc.
That said, a sympathetic SW or GP is a good first port of call.
I send best wishes to you all, and hope things can be managed before a crisis hits x
Solidarity ❤️