How sad! My father-in-law died of the disease a year ago.
He was a psychiatrist who managed an Alzheimers ward at a VA. That was bad, because he told me, "I know what the future will be and it's horrible". My 14 years as his caretaker made me commit to nursing home reform.
I followed Campbells career from his first Rock and roll hit, "Turn Around, Look at Me, in 1962. Then , I had the privilege of playing the same venue in Barstow California, along with Buck Owens, the Browns, the Burnette brothers (Tommy and Dorsey) and others.
Hell of a player!
What a shame.
Russ