Suggest Treatment For Deterioration Of Motor Skills

Hi, what is the treatment for the deterioration of motor skills? My dad is 68 and is losing control of his left leg and slowly his left hand as well. He has no pain but is now dependant on a walking stick. He was a builder for most of his life. He has had mri's and ct scans as well as a lumber puncture and all of the results were inconclusive. How can I help him?