Lots of people talking about how tiredness Can affect the mobility of our cared for. I have found that it's how tired F's brain is that causes the problem. This can be a long day with a long drive upset things for at least 3 days. Or a stressful day at The computer. I usually have to plan things with easy quiet days in between and insist on naps. Although naps usually happen spontaneously. We can go from walking stooped forward with arms dangling to standing upright with shuffling feet.
I have found one technique for those moments when F just freezes and don't know where to put a hand or a foot. If I point out the next task, ie. Getting up from sitting to going through to next room, I tell him he has to go through the door way. This desease is difficult to fathom. If F was walking in garden he needed a stick or a hand. Give him binoculars or a camera in his hand and he's off like a whippet. I have in the past walked in front of him with a glass of beer, that worked.
F has a need to curl his fingers a grasp something, often not letting go. If I give him a hand to grasp this is often enough sometimes. Other times he needs a lift.