Oh speed dear it's like everyone wants to be the boss of everyone else in this situation. They are making it more difficult than it needs to be. My advice -

Agree with your husband it's absurd you have to go through ER (it is really absurd and waste of time, but you may just have to follow their stupid rules on this one)

Agree with intake nurse that their doc will have to deem it necessary or not (they will likely agree your pdoc's assessment, this is a well know bp depression treatment that has worked for you in the past. This intake nurse is just having a little power trip over you because who cares it's her personal attitude problem)

Just get there, give hubby a hug, tell him you love him.
These kinks will get worked out, and it sounds like help is on the way.