My dad is late 70s. During lockdown he developed what was thought to be carpel tunnel - Tingling and numbness in one hand but not the little finger. It has slowly progressed to numbness all the time in that hand. He now can’t carry a cup, do up his buttons etc. the gp referred him for surgery but after seeing the specialist they did some scans and said it’s diabetic nerve damage and that surgery won’t help. 
My poor dad is already In poor health and has depression and is now even more depressed. He doesn’t know how he can carry on forever more like this.
Is there anything that can be done to help regain some feeling in the hand? Any alternative treatments?
I feel so sad for him and wish I could do something to help.