Can the assisted living facility increase my rent for the full amount of my cost of living raise which is 5.9% this year?

You say you are on disability, does this mean that Medicaid pays your AL rent?

If yes, then that is the why. You can't double dip and have more income and have Medicaid paying as well.

Your personal needs allowance is all you get when you are receiving public assistance.

Can you come back and let us know if you are in fact on Medicaid as well as SSD. Thanx.

ALF can ask what they wish. They are basically rental contracts with levels of care added. They usually enumerate in their intake papers how much of a yearly raise you may expect in normal circumstances, but of course there is nothing normal in the times of Covid-19 and now we have inflation. The facilities make their own rules and are not regulated in the same way nursing homes are. But of interest, nursing home rates are rising as well now, just as our cans of cat food. Everything is going up.
Their costs have gone up just as ours have.

I wouldn't think they can raise your rent if you have a contract for a certain rent already.

Does your contract spell out what you're supposed to be paying per month through June '22? If so, show it to the people billing you for more and tell them they're in breach of contract if they raise it before then.