I met Barton a few times here for dinner etc, and like everyone am very sad to read this.
I do know he admitted he was in very poor health for a man his age, with a couple of major ailments, and had great difficulty in walking any distance.
He was easily the most travelled person that posts on FT I believe, doing about 850,000 paid flown miles a year in recent years, and how he ever got time to fulfill posting and moderating on FT with that almpost impossible schedule, and running a large company, I will never know.
He posted only a week or two back on UA that his travel had been scaled back enormously and he was greatly looking forward to that.
A warm and friendly and generous Flyertalker, and he will be greatly missed. My condolences to his wife and family.