Although I cannot help you with regards to the procedure they intend to perform on your boyfriend, are you sure this condition is diabetes related, has he been told this is the case?
Diabetic Neuropathy is a condition that effects the nerves, and is common in long-term diabetes, or where control has been consistently erratic over a shorter period. However, there are also other conditions that may also be the cause, for example repetitive strain injuries due to work or sports, so not everything is diabetes related. In any case, I hope all goes well and his condition improves!
Nigel