Full-Time Scam
There is nothing worse than when people try and take advantage of other people that are vulnerable in some capacity. If someone is doing a task, any task for a certain amount of time, people should definitely be compensated for it.
No doubt in my mind that this woman needs a full-time caretaker, but it isn’t particularly nice trying to scam someone to do the job. Asking someone to pay for board and rent, when they are already not getting paid for their job is a very sneaky thing to do.