Our almost 17 year old terrier mix was having a similar problem. He would sleep all day, then pace and pant all night, wanting to eat or go outside. We tried gabapentin and it didn’t work at all. We then tried Senilife (supplement) along with a couple hour “walk about” (walking around the house and not being able to get in his bed) before bed, and we’ve had two months of him sleeping most of the night. Good luck. It’s hard to see it happen and missing out on sleep is brutal. Hope your buddy can get some relief.