hi Sandie,
Just to let you know, my Dad was in much the same situation as your MuM,though he was 74 when his PP levels went from 6 to 24.
he didnt find the biopsy that painful. he was put on MPT, and didnt have any major side effects. his PP levels became undetectable after 4 months, so he was taken off the MPT. he just gets his blood checked every few months to keep an eye on his PP Levels. Thats them been undetectable for 4 months now. Fingers crossed.
Dont know the procedure, but I'd imagine you could ask the consultant if it is possible for the biopsy to be done under an aneasthetic.
All the best for Christmas