Mildly demented spouse refuses to see a doctor of any kind for ongoing care or assessment, including in-home care. What to do?

What sort of in-home care, and why is this only the one spouse's decision? What's stopping the other spouse accepting/hiring it?

The choices become 1) waiting for an event to happen that forces change, and it will happen, or 2) making your help conditional on him/her having a medical evaluation