My husband used his expired license at doctor's offices and we had no problem. Then one day he threw it away. When I asked him why he said it was expired so he didn't need it. Sigh. So I had to take him to the DMV.
I also use my mother's expired driver's license as an ID for doctor's offices. I have never had a problem. Like you, I want to avoid taking her to the DMV and waiting in line for a new ID.
My parents [in their 90's] used their expired photo licenses all the time.
In my State, one can order a new license on-line through the State's Division of Motor Vehicles. If it is for use as a photo ID and not to use for driving, the photo they have on file can be used if the photo isn't very old. The new license is mailed.
You never know about things like this. When I submit my cousin's license, they barely look at it. But, you never know when that could change. I had to submit my driver license to rent a carpet steamer at a grocery store once and they denied me, because my license was expired!!!! Seriously. I laughed all the way out of the grocery store.
In my State, one can order a new license on-line through the State's Division of Motor Vehicles. If it is for use as a photo ID and not to use for driving, the photo they have on file can be used if the photo isn't very old. The new license is mailed.