Dogs and people have evolved alongside each other in pert due to dogs' ability to mimic facial expression. People and dogs appear to find it more difficult to discern the facial expression of black dogs and so they are perceived as being potentially aggressive out of caution.
Three out of my four dogs were black (the fourth one got his paws under the table by accident) and that was because black dog hairs don't seem to stick to everything like lighter coloured fur. I found them all very facially expressive, but they were mine and I was familiar with them. I have noticed more difficulty reading a black German Shepherd than the lighter colours.
If it has a bearing on his life now, it has a bearing on his life now.
Unless you've got a magic wand to make it all instantaneously go away, I think you're kinda telling him he's not allowed to feel how he feels, or process his stuff how he sees fit.
RE: If You Had A Pet Aussie............
I'm a tailor, I can take them in for you. *beckons Micky seductively and whilst whipping out her tape measure*