@STEM2017 Yes the NY documents are the right ones to have and the only ones S needs. These matters are controlled by one’s primary residence, not a temporary place like an OOS college or an OOS hospital/health facility.
By the way, I read some comments above suggesting that signing powers of attorney and health care directives may be overkill. I completely disagree. I think it’s really important for 18+ year olds to sign these documents to firm up who has authorities to act for them. Yes, a parent (like the one above) may be able to skate by for some time without these documents, through some combination of provider-specific directives, joint accounts, and the good grace of the people the parent is dealing with at the time. But that is risky behavior and there is just no reason to take on any risk here. I often have had to help families go to court to get “guardianship” and/or “conservatorship” - very expensive and time consuming propositions - in situations that easily could have been avoided had the now-disabled-or-incapacitated person just signed these easy documents when able.
As I wrote above, in many/most states, powers of attorney and health care directives are state-approved forms - probably available online or at a library. And even if you use a lawyer for this (which isn’t required), often they will handle this for free or very low cost for children of their existing clients. Getting this done is easy, and likely free or low cost - and just good planning.