I understand that he lacks vision and hearing and of course his background means that he is very different from my old blind dog.
Everyone will look at this differently, KC. I think that you have come a long way with him. He no longer bites you and you say that 'he likes a pat on the head'. So, he does interact with you. It may not be in the same way as your other dogs but 'in his way'. I would consider that a success for Denzel and for you.
Avoiding the other dogs is probably a wise and sensible thing for him. He can't see to read their body language. My Flattie had to be watched very carefully as he was so friendly to other dogs but couldn't read their language to know that they were saying 'back off' and so they could be aggressive towards him as they couldn't work out why he was still bounding over. Denzel is safer in keeping his distance.
Between 7-12 years old you think. Well, gait does change with age. My Flattie moves differently at 10 than he used to as a young dog. Only a vet could assess , with any certainty, if this was just age or a specific problem. Many of my old dogs ended up taking some pain relief to help with movement as they aged.
'Howling'. Well again, IMO, only a vet could find out if there was an underlying problem. Probably wrong to assess on a forum. Example, my old blind dog (and hearing did fail as he got older) would howl to certain very specific sounds ..... A certain note in Emmerdale theme tune, certain point in washing machine cycle, motorbikes, etc.
I tend to use a similar 'think list' as Doganjo. An old dog, particularly with problems, is not going to enjoy life in the same way as a young dog and the list just helps you think calmly about it.
I personally think that if you are having to ask on here then the time to say goodbye is not now. I think that when it is your own dog that you can generally just feel that the time has come. I've usually been able to tell when my oldies have had enough and no longer have any enjoyment .....
