Is he having seizures?
We looked after our friend's dog recently and were really concerned that he was suffering with seizures. Each time he laid down, he would start to fall asleep, and just as he was dropping off he would twitch and startle, sometimes wobbling, and would often jump up and pace around before settling again. He would do this pretty much every time he started to fall asleep, so just wouldn't get any sleep in the day. I have over 10 videos similar to the one attached. Overnight it seems to happen less. We have a dog ourselves and know what it looks like when they dream, and this seems quite different.
Our friend took him to the vet and they ran bloods, but said all looked ok and he was probably just feeling unwell (he had a pancreatitis flare up around the same time). Does anyone else think that it's more than that?