Continue Fosamax at 97?

My mom has been taking Fosamax like clockwork every Thursday morning for years, definitely more than 5. She took it several years back as well before stopping for a few years. She seems to have benefited from it. Her bmd has improved to osteopenia range, though I realize that doesn't mean quality bone. She hasn't fractured that we know about, although I suspect there may be compression issues in her upper spine, and she's lost a few inches. She's quite active still. She's a former professional ballet dancer who still teaches a tough class 3 times aweek. Good balance flexibilty and strength for her age.
Now, as I'm finally learning more about osteoporosis unfortunatrly because of my own recent diagnosis, I'm wondering if she should stop taking Fosamax and enjoy a little drug holiday. She's all for the idea. She has an appointment with her pcp on Wednesday. I'm quite sure her doctor will want her to keep doing what she's doing, not rock the boat.
I would not want to encourage her to stop taking it if it could potentially lead to fractures, but also fear that continuing could do the same.
I havent found info or studies that extend into this age group. Does anyone have experience with Fosamax at this age, or wisdom to share? Thanks!