At age 56, I had Gamma Knife surgery 20 years ago on bilateral acoustic neuromas. The good news is that it preserved hearing all this time. Outside of minor sores in the forehead healing quickly (from the frame) and very slight nerve damage in the face, there was no pain. I did not notice any fatigue. Perhaps procedures have changed in the last two decades, however, I’m very grateful to have had GK surgery. I wish your partner the very best.