My father has Parkinsons Plus (Progressive Supranuclear Plasey). Doctors have told that he may not live for more than 2 years. How can they predict so accurately? His condition is deteriorating day by day as he is showing inability to walk even with support. His speech is very much unclear. He needs to excercise for longer duration of time now a days. I dont want to let him die so early. He is 58 only.