How can I find POA paperwork and will? I'm POA and never received a copy.

My money is that it's in a safe deposit box, which of course is the worst place to keep wills, trusts, and POA paperwork. No one can access the box without the paperwork that's kept in the box.

Geaton, the person appointed as POA does NOT have to sign anything on the POA form. It is the person who is designating someone to be their POA who is doing the signing. My own attorney had me sign my POA but the person I appointed did not. When my aunt appointed her lawyer prepared her POA/successor POA she signed in front of notary but the POA did not.

How do you know that the paperwork exists?

Any cancelled checks in his home? My.Mom kept themself years. Maybe you can find cancelled checks to an attorney. Or check register or credit card statements?

Search the house. Does your grandfather have a safety deposit box at a bank?
If you don't know the law firm who did the POA and can't locate the document, your father (who is grandfather's next of kin) needs to go to the probate court in your town and petition for POA and conservatorship over your grandfather. Your father can tell them at the court that he refuses it and you can accept it. Go with him to the probate court. They will help you and your father.
Is your grandfather out of the hospital?
If he's not you and your father need to ask to speak to a social worker at the hospital and ask for a 'Social Admit'. Tell them that you both refuse to resume care for your grandfather until one of you gets appointed POA and conservator and that he is an unsafe discharge. They will keep him in the hospital until they find a nursing home for him to go to.
If you want to take care of him get conservatorship and when that's done let him come home. Or not.

I think the original writer had left the building. It has been 2 weeks since the question was asked. Hope everything is ok.

More than likely, IF he ever got a POA done, a copy is somewhere in his house. They aren't filed anywhere like a courthouse. Unless you live in a small town, you may never find the atty who wrote it for him. At this point, you probably just need a new document so getting that will be the real solution.

You might start with a police report that documents his state of mind, the accident and that they took his license. Go get a consult with an attorney to find out if that's enough to establish incompetency to be over his affairs. If his child(ren) are living, it may have to be one of them.

You should ask all of his children if they have a copy of the will (and POA). Once he is deemed incompetent, he will not be able to write a new will. So that means, when his life is over a probate w/out will would have to be done and his leftovers would just be divided between the living children. If no children, then to siblings or grandkids, I'm sure.

You might ask him again about these documents. Remind him they took his license and w/out the license he can't get the car back, but if the two of you could find the POA, you would be able to help him get the car. Just tell him, insurance company wants to help him and wants to see that you were given permission to help him out.

I do question that you say you are POA, but never got a copy of the document. Have you ever handled any task for him as his POA...and how did you prove you were POA? Or did he just tell you you were, but never had to actually do any thing for him that required a POA?

If he doesn't have a diagnosis of being incompetent to handle his own affairs then you cannot act for him no matter what POA papers you have.
Is this a DPOA done when he did his will? If so you will need paperwork from two doctors attesting to the fact your grandfather is no longer competent to act for himself to begin to act upon it and get it in place.
If you cannot find a will or other papers in his home, which you should now scour for said papers, then you are left to become his guardian if you wish to. If he is hospitalized the Social Workers may be able to get you emergency temporary guardianship if he is adjudged not competent.
Your not having ducks in a row for this concerns me as I wonder if you know and understand what/ and all that is involved with serving as POA. At the time you take this on, if he isn't competent, you are responsible for everything, including ever single penny into his accounts and every penny out. You will be signing everything as his name with yours as POA. You will be legally responsible. This is a big job.
So contact social services at once. Tell them where this stands. Who has keys' to granddad's premises? you need to look for the will which I assume has the DPOA in it. The very sad thing is that most seniors, thinking this is SAFE, lock them into a safe or into a lockbox at their bank. As guardian you would have access to such places, but this enters into legal realms you may not choose to take responsibility for.
You may, in all honestly-- and I say this after taking on POA and Trustee of Trust for my bro willingly and knowingly-- be the better off for it.
I sure wish you the best of luck, but acting as POA involves a year of dreadfully difficult setup at BEST and that with a cooperative and competent person conferring the duty on you. I hope you'll update us.

Granddad has given you quiet a scare.
He may settle a bit in a few days. He is most likely very stressed with all the recent events. Make sure he is not dehydrated and does not have a UTI. If you can’t get him to his primary for a checkup soon, you can get this checked out at an urgent care. Either can cause him to be more confused and less likely to remember and could have been the reason for his accident.
After he is calmer it is possible he can sign new paperwork if the old doesn’t appear. Notice the time of day when he is sharper. Make an appointment with an elder attorney with that timing in mind.
The attorney will want to speak with GD alone.
Usually a bank will allow him to have someone else listed on the account as long as he is with you when you go to the bank.
Did the police give you his license back? You might need that for ID.

Go to your county clerk's office. It should have been filed there. If it wasn't, there is no POA at all. If there is none, get one written and have him sign in front of a notary. That may not be easy but it is necessary. BTW, no matter his mental status, unless he has been officially diagnosed as dementated he can still legally sign the POA. If he has been so diagnosed it is too late. See a lawyer, a court order might be necessary. You have a tough situation, good luck.