Random barking in the night

Try a white noise machine to mask any sounds he may be hearing.

It may be that he can't hear normal sounds very well but other types of sounds distress him so anything that provides a constant noise might help with that. Failing that not sure what else could help other than check the temperature isn't waking him up with being cold etc.

My friends dog is deaf and still barks at ‘things’. We were trying to work out whether although he can’t hear that maybe he picks up on vibrations or smells or he may well still be able to hear certain frequencies of noise. Whatever it is he starts barking and doesn’t stop for ages! Almost like an anxious barking.

Anyway Adaptil and a Thunder Shirt to reduce anxiety has helped significantly and then she moved him to her bedroom (which is not everyone’s cup of tea of course) which has apparently reduced it to a brief yap once or twice a night.

A dog with bad hearing is more likely to be startled by things as he's not as aware of his surroundings. Could light be getting in from security lights being triggered by animals or people walking past?

My dog will very rarely bark in the night but it's generally when someone's walking past our house talking on the phone.