Blind Dog Sleep Schedule

One of our dogs is 14yrs old, diabetic and now fully blind for about a year. He seems to have his nights and days mixed up because he sleeps soundly for 99.9% of the day and then at night he’s restless, wanders the house, and has now started randomly barking at odd times throughout the night. He has never really been an active/playful dog, especially since getting older, so I’m not sure how to provide enrichment for him (especially not food based due to his diabetes) to keep him awake more during the day so he’ll sleep throughout the night. Since going fully blind he will not walk on a leash/harness, so walks are a no go unfortunately. The vet said at his last appointment that he could be getting some doggie dementia and that his blindness is not helping that either. Has anyone else experienced this or anyone have enrichment activities I could try?