I was diagnosed with giant cell arteritis/temporal arteritis over 3 and a half years ago. The steps your dad’s doctor has laid out for you sounds exactly like what happened to me. First I would like to ease your fear about anesthesia. I was just given shots in the temple to numb the area and the doctor took the biopsies and stitched me up. So far that has been the easiest part of this disease. I was put on 60mg of prednisone before I ever had the biopsy and have to say that I felt better within 48 hours. The problem comes when you have to reduce the dose of the steroids. I did fairly well until I got down to 20 mg. After that through trial and error We have learned that if I go down more than 1mg a month or sometimes 1/2 mg I start to have more inflammation and pain. I have been on a new drug for about a year now called Actemra which is a shot one day a week . The theory was that maybe it would allow me to get off the prednisone quicker but that has just not been the case. The up side is my bloodwork has been great while using the shot, but I still have relapse type issues but without the corresponding rise in c-restive protein or seed rate.
I wish your dad all the best