...is your gay partner going to be allowed so sit vigil by your bed in the ICU? NO. Why not? Becuase "only family is allowed in the ICU". No amount of general power of attorney is going to override that bit of provincialism.
And as far as having the same tax arrangements as does a married couple, why shouldn't they?
(And no, I'm not accusing you, daemon, of having a gay partner. That's the "collective" you.)