[Cboldt]

A husband is exercising his state-law-given right to make life or death decisions about his incapacitated wife.

Not exactly. The husband is carrying out his wife's wishes to be starved to death. Spouses have no right to make medical decisions for one another. Medical decisions are strictly an individual prerogative. In this case, since the patient's wishes weren't in writing, a court determined the patient's wishes, to the standard of clear and convincing, taking testimony from several people. The husband does not automatically win this evidentiary exploration. He did in this case.

[BikerNYC]

Spouses have no right to make medical decisions for one another.

Absent a Health Care Proxy, which, in NY, specifically permits one individual to appoint another individual to make all medical decisions in the event of incapacitation.