Hon, I know EXACTLY what you're going through. My dad has PD and also severe back problems. He has a walker, cane and wheel chair and absolutely refused to use them for a long time. I think they fight it so much because the feel if they use it, then they are giving into this disease and they will have to face the fact that it is getting worse. The position you're in is a tough one. On one hand, you don't want them to get hurt but on the other you don't want to make them feel like they're dependent on you or talk to them like they are a child. My advice, pick your battles. I know you don't want to see him fall, but sometimes making a big deal out of it only makes them more determined not to do what you're asking. In time, he'll realize he has to have it. Good luck!