Sharon is his daughter, and from what I have read, they share the same business methods! There was a documentary on TV not long ago, where the story was related about a would be manager who tried to steal the Small Faces from him. This guy was taken to a very high building, held by the ankles, and held head down over the edge. He was released when he promised not to try and poach any of Don's acts. Another time, again this was the Small Faces when they were starting out, they had finished playing, when the manager of the hall tried to short change them. They phoned Don, and was told to wait. The heavy mob arrived, and broke the Manager's leg with a hammer, but not before he had paid the correct amount.
Just a sideline, one of Don's 'helpers', became manager of Led Zepelin. He was 6ft 4ins, and very aggresive, but he made Jimmy Page and the boys multi millionaires.
Perhaps 'Byard' has a few tales of this nature.