I have read that 1 injection of Prolia and stopping with out a bisphosphonate won’t cause the rebound, probably.
But anymore than 1 will. I think your doctor is wrong.

I have been on a number of osteoporosis meds including, fosamax, Bonita, Forteo, recast and most recently prolia. I had 4 shots of prolia. Just prior to my shot in November, I had a stress fracture in my left foot. I was supposed to have another shot of prolia and I recently had a femur break. I cancelled that shot. My endocrinologist is not suggesting evenly as she said there is not enough evidence that it would be helpful to someone who has had a bone break. I think she is leaning toward Forteo. When I took this drug, about 10 years ago, (for 2 years), the literature indicated you can only take Forteo for 2 years in your lifetime. I tried researching, and have not found any current protocols. The issue with stopping prolia is that you are subject to spinal fractures.