If you haven’t already done so, you might want to start bringing him his favorite music from a key time in his past – perhaps some Frank Sinatra ballads from when he was courting your mother? (Just guessing here – my parents used to go all ga-ga whenever they heard Ezio Pinza singing Some Enchanted Evening… anything from South Pacific made them happy!) Sometimes the powerful associations with love and joy will get through the fog.
The smell of favorite foods might do it too. The nose sometimes knows what the neo-cortex has forgotten. So perhaps you could make a special effort to bring him a beloved dish, scented with long-ago, happy, olfactory memories. You don’t have to make it yourself – just find a restaurant that can serve up a weekly order of it…
Therapeutic massage might speak to his muscle memory in a way that words no longer can. Gentle, nourishing touch bypasses the thinking brain and literally gets through the skin.
And the soothing words and calming music on our guided imagery for Healthful Sleep could help with his sleep too – again, the voice tone and music get through to the primitive brain even when the words have lost their meaning. Same with imagery for Stress during the day.
In other words, appeal to his senses. You may be able to connect with him there, and give him some comfort and solace.
All best wishes,