It would indeed be horrible to watch. I recall that he had a couple of sparring sessions with Eddie Mustafa Muhammad around this time.
I know he had a well publicized exhibition with a young Michael Dokes at some point. I can't remember if that was in the late '70s or early '80s.
I believe that was just before the Young match... Ali was quite chubby/soft in the Dokes sparring session. Spent the entire fight in the corner basically, taunting Dokes. He didn't come into the Young match too much lighter. :think