Maybe you can find an old laptop for cheap and salvage the keyboard.
I don't know which resources are available to you, but you might
Go to a scrap yard (preferably one specialized in electronics) and search for a broken laptop with the same keyboard. Scrap dealers are mostly interested in the metals, but plastic keys are worthless for them.
Use online ...
If possible, exchange the part(s) with their twins from rarely-used keys.
After you have gotten the weakened part into a low-traffic position, some replacement or repair can be done to lengthen its useful life.
Comment: I find that some of the materials used by dentists and dental technicians are as high-tech as they come. Many materials exist to bond, build-...