Does anyone know what portion of memory care is tax deductible? Both facilities my loved one has been in don't itemize billing.

I was able to deduct 42% of her rent when my mom was in MC. I also itemized medical co pays and legal services

If your senior is self paying all their bills then know that the portion that is "medically necessary" if covered. That's usually not enough to qualify for federal tax deductions.

This from online:
"If you or a loved one live in an Assisted Living or Memory Care community, all or part of your care costs may qualify for the medical expense tax deduction.
The medical expenses included in the fees for Assisted Living or Memory Care can be written off on taxes—with some qualifications and restrictions."

As you can imagine this is complex. You can go to the IRS site and research, but it is often easier to discuss this with a CPA who can give you the rules. I would do that. The memory care unit would supply what portion of expenses are considered "medical"; they are required to do this by law.
Trust me, having been through this for my brother, it has to rise to a pretty high level for them to get tax deductions, and it seldom gets that high. But again, this is kind of a question for experts. When you need medical you see a doctor; legal requires an attorney; financial needs its own experts. Wish you the best of luck.

IF you are POA then a visit to the memory care admin with "I am responsible for filing taxes for Dad and my CPA needs to know the medical expenses for his care so he can know if he has a tax deduction" the Administration can supply this for you.

This is a question for a CPA, an actual professional trained to give you an accurate answer for your situation and home state where you are filing.