Question: 

"I'm frustrated that my father has no motivation to regain his strength by following the therapist's exercise recommendations and plan. I believe he could regain the functions he has lost, though he will not put in the work. His lack of motivation baffles me. He actually seems more comfortable doing nothing than pursuing the work necessary to be as active as possible. It is very hard to watch my father's decline. Do you have any recommendations for motivating him?"

Answer:

The wonderful thing about your question is the fact you already understand that regaining strength is not up to you. It is up to your father. I would say that you are halfway there. You understand that it is not your call. So often we wish our goals and aspirations onto others, assuming they will magically follow through.
 

Now for providing a little motivation.

The best way to accomplish anything is to have an end goal in mind. The same is true of your father. For him to be motivated, there must be something he wants to accomplish. I rarely see a daughter’s,  therapist’s, or doctor’s goal accomplished unless the patient shares the same one.   The goals need not be lofty, though they must be the patient’s goals, I repeat, the patient’s.

It is time to find out what he wants to do that he cannot do now. Ideally, you or a professional would take the time to find out what he has in mind. Maybe he wants to mow the lawn, walk around the block or get in and out of the car without assistance. He may simply wish to live without pain.

Sometimes we need a professional to help us connect the dots between the end goal and the work it will take to get there. The more a person wants to reach the goal, the more likely it is they will put in the work required to attain the goal. That is why it is so important to figure out what the patient really wants.

Your father’s quality of life matters quite a bit also. Being engaged with family, friends, and neighbors makes life rewarding and purposeful. Being isolated and alone takes away a jest for life. It can foster a disinterested individual, increasing the likelihood of depression. Lack of motivation is often the byproduct of a lack of purpose and meaning. Planning events, projects or some form of work will keep a person engaged. Endless days with little to look forward to, other than the next meal, can zap any desire for rehabilitation or improvement.

I do not believe you can give another person your motivation, but you can help them discover their own and help them to find purpose. It all starts with a simple conversation. 

I wish you the best in this endeavor.