I think your progression is alarming and rather fast for diabetic neuropathy.

It might be a good idea to get another medical opinion.

Stress issues on your hands from using crutches would not impact the last two fingers as much as the first two and thumb.
Your issues with the last two follow a dermatome from the neck:
http://www.apparelyzed.com/dermatome.html

When I had my severe hand issues, from carpal tunnel due to my low thyroid, it was the thumb and middle fingers affected.
I used night splints to take the pressure off the carpal tunnel.
examples:
http://supports4less.com/bodyparts/wrist/index.htm
There are many types/price ranges.
I still use them occasionally now, if I overdo working with my hands. I also use the wrist braces that weight lifters use when digging in the dirt gardening. This keeps strain off the nerves in the wrist.

They are like these, only by ACE and flesh colored:
http://www.newgrip.com/wrist_brace.html

Do not wear them too tightly.