At 89 I would think your father would have options. Xgeva is for bone strengthening, If it’s not working well, you could switch to Zometa, Another injection that works pretty much the same way.

An easier solution would be for him to switch to Fosamax. It’s a pill you take once a week and it does the equivalent of what Xgeva does with minimal side effects. I was on it for 5 years. Ask your doctor about other options.