muscle loss in arms and hands

Hi, my dad has had severe muscle loss in his left forarm and left hand along with his right bicept. This has been going on for about fifteen to twenty years.
He has seen a neorologist about it and gone through testing but found no answers. Along with muscle loss he says that his arm and hands sting alot more so when it is cold outside. His left arm from the elbo down and hand looks like a skelleton with skin on it. I do not think it could be ALS because he would be dead by now. The doctor he saw thought it could be from an accident he had when he was fourteen years old, and there might be some nerve damage in his back. He has been a heavy smoker for most of his life. Never been over weight and has good health other than his arms and hand.

Does anyone have any ideas on what it could be or what to look for. Also is there a prostetic arm that would fit over his current arm to help him with day to day life functions.

[chillcaro1]

My husband is having the same problem.  It is in both hands and arms.  His hands have no muscle and he is loosing the ability to use them.  He compensates with his upper arms for strength.
He is afraid at times to use knives other tools.  We have been everywhere for 10 years and still no answers.

He to was in a car accident about 16 years ago and he does have some spinal damage in his neck.  While this is not causing any other problems we were told that this could be the cause.  However, we continue to monitor and forge on for more answers.  I refuse to accept that this is the cause.