Most of the cost of assisted living is paid with Welfare. You must use all of your assets up, become eligible for welfare and then welfare picks up the tab from that point forward. Welfare is a 50-50 Federal-State program, with the state matching funds from the Federal Government (at least technically, Congress ends up paying for most of the costs by providing additional funding for the states). Now every state in the Union can opt out of the Federal system and fund they own system, but none have, all states want the Federal Money to pay for these programs and thus follow whatever Congress has set for this program. Thus assisted care programs are technically State Programs, but subject to Federal Rules for those rules come with the Federal Funds and no state wants to run their system without those Federal Funds.
Now, she can AVOID having to pay these fees via two huge options, first give her property away to someone else and do NOT go into assisted living for Five years. Congress has said if someone gives property away within five years of going into an assisted care home, that home can undo that transfer and use that asset to pay for the cost of the assisted care.
The other option is if she has a spouse, they are restrictions on what the home can do when a spouse of someone in a assisted living home still lives in the family home.
There are other ways to get around this CONGRESSIONAL MANDATE, but these are the two big ones. This is all driven by a desire to minimize costs to the Federal Government.