I don't know what state your grandmother lives in, so I can only provide general information. But in California, copies of estate planning documents would not be acceptable to the Probate Court unless there were "clear and convincing proof" that they had been unintentionally misplaced. That's a very difficult standard to meet, especially if the documents include gifts to people who would not be considered the "natural objects" of your grandmother"s "bounty" - in other words, gifts to people who are not family members or close friends or charities she has consistently supported over the years.
If your grandmother wants to make sure that her intentions are met, she will need new originals. I'd suggest that you check with the lawyer who originally prepared the documents and find out if s/he will prepare a "restatement" (of a trust) or a "codicil" (to a will) that acknowledges the original documents and charge a much reduced fee.
I know that I keep copies of my clients' documents in word format on my computer. It's relatively easy to re-run them, and if there aren't any changes I only charge for the time it takes to sign them & notarize them (key: "no changes" - if the client wants to make revisions - other than things like typos that we missed the first time - then I'm going to charge for the time I have to invest in making those changes).
If you have photocopies of the documents, nother possibility (at least for a trust) MIGHT be to have your grandmother sign the photocopy with the same formalities as when she signed the originals - so, for example, with a trust, her signature would probably need to be notarized (at least in California) and she would need to sign her will in front of witnesses and have them sign again as witnesses. In some states the signature of the "testator" (the person who's creating the will) or the signatures of the witnesses or both need to be notarized - that's not the case in California. But you need to check the laws of your grandmother's state and make sure those laws are followed to a "t".
If you have photocopies of the documents, you might also ask the original lawyer to supervise the signing of the replacements - again, s/he should not charge anything approaching a full fee for just overseeing the signing of the same documents that s/he prepared before.
Hope these ideas help.
This information is not intended to substitute for professional legal advice and does not create an attorney-client relationship. You should accept legal advice only from a licensed legal professional with whom you have an attorney-client relationship.
The proper answer to your question depends on the state in which your grandmother lives.
With that said, in Florida, copies of powers of attorney and healthcare surrogate designations are often respected by financial institutions and medical providers, assuming there is no evidence that those documents were revoked. Copies of a deceased person's Will can be admitted into probate; however, the presumption under the Statutes is that a Will that cannot be located was revoked, unless evidence to the contrary is presented to and accepted by the Court.
To avoid all of these concerns, your grandmother should ask her attorney if he will assist her in executing new documents. If her wishes have not changed and she is of sound mind, then her attorney should be able to produce the documents for signature without significant expense.
Michigan -- Assuming your Grandmother has not changed her mind regarding how she's distributing her assets in the COPY of her Will you've got, you can, upon her passing, submit the COPY of the Will to the probate court along with an affidavit stating that Grandmother had not previously revoked that particular Will and that you've looked everywhere for the original and are unable to find it.
However, if she's able and still has legal capacity, she should execute updated documents to be safe. Typically the cost for a will, health care power of attorney and financial power of attorney for a single person is under $500.00. Good luck!