Take a look at the buy-in contract itself.  If they are buying into a continuing care retirement community (also called CCRC), then a portion of the buy-in is deductible - the percentage is based on the percentage the COMMUNITY uses for deductible medical expenses.

If they are buying into a Skilled Nursing Facility, then the Purpose of the community is solely to provide medically deductible services, and the buy-in is 100% deductible.

This article is not authoritative, but readable and refers you to the right places (Baker court case and Revenue Ruling 93-72)

https://www.marketwatch.com/story/you-can-deduct-these-retirement-community-fees-as-medical-expenses...