If my name is on the Medical Power of Attorney do I have a legal right to see it?

In my personal experience, if you are appointed backup POA you don’t sign the documents. So you might want to ask the facility if you are a co-POA or backup. When my MIL had her trust paperwork drawn up, my husband was assigned POA and he signed the document. His siblings were backups and they did not need to sign. Same with my parents when they had their paperwork done, they are each other’s POA so they either. Brother and myself are backups and did not sign.

My brother and I are POA's for my mom and we both had to sign, in front of two witnesses, also in front of the attorney who notarized the documents.

Yes, call for a phone consultation with an elder law attorney. I found my aunt's copy in her belongings at our home (she planned on moving here) and called both the our state and her out-of-state listed attorney to check out the legal status of the document in our state.

Do you have a copy of a healthcare directive which names you as the primary agent? If there was a prior document to the one the daughter had drawn up, then I believe the agents removed would need notice of the power of attorney being revoked.

If it's a matter of visitation at this time, is the care home accepting visitors even with the lock-down or as an exception to your sister's hospice status? Can you try to communicate with your sister's daughter since this is best as a family matter?

In most states the person(s) named as PoA must be willing and present when the PoA papers are notarized in front of the witnesses. If you were assigned any PoA you should have been given an original copy of the documents (all parties get their own signed original). If you don't have this you may not have ever been PoA, or else some misunderstanding has maybe taken place. Not sure it is worth going to an attorney. If you do you will need to have some evidence to support your case. And it will be pricey and time consuming. Also, if you are successful in bringing your sister home from hospice (presumable from a facility) you risk exposing yourself to Covid-19. You may not be able to visit your sister in hospice but you could ask your niece if it is possible. At any rate your risk exposure. Just something to consider.

Yes. Attorney. NOW. Let her know that is your intention to do at once.

In my experience, any proxy under any Living Will (medical POA), or POA or DPOA MUST sign an acknowledgment that he/she is willing to accept that responsibility.   This may vary by state though.   Duplicate (conformed) copies are signed, and each proxy is given a copy.

What you need to find out are (1) whether your name in the document provided to the care home does in fact name you as co-proxy, or subsequent proxy, or if it specifically excludes you from any authority at all, which is something I began to question when you wrote the home will not provide you with a copy.    OTOH, folks there probably do not want to become involved in a family disagreement.

If you're old enough to participate in your local senior center, find out if it (and others in the area) have free legal advice, sometimes weekly or biweekly (although that's probably not the standard now during the pandemic).   Then ask a few attorneys from different jurisdictions, and in the meantime find a qualified estate planning or elder law attorney for a brief consultation.

Alternately, you can search for {your state}, POAs, distribution of copies (or something similar).  

Here's a hit for Michigan, with information in the 3rd paragraph category, affirming that a proxy must sign as well:

https://www.michbar.org/public_resources/probate_dpoa

Your profile doesn't include your state, but you can do some research to see if you can find similar criteria.   If it requires proxy signature, and you don't recall signing, then there's a good possibility that you don't have the authority to act on your sister's behalf.

This is a good question. Think I would call Legal Aid to ask that question. If you have yours on file with the NH, then hers should have been questioned. If its not on file, I would produce yours to show there is now a conflict. I would wonder when hers was assigned. If during the estrangment then I would question the authenticity.