Many musicians naturally prefer to put friends and hangers on into business and advisory roles instead of finding and hiring the best they can get. Part of the hard lesson for musicians is that good and honest managers, lawyers, accountants, and financial mangers are expensive and are almost always straight laced types who do not live like musicians and lack an artistic temperament.
As for Brian Epstein, the so-called "Fifth Beatle," his commingling of the roles of friend and manager invited problems, as did his amphetamine use. The Beatles have cause for complaint as to Epstein's contract terms and business dealings, but they invited that trouble by their own carelessness. And the Beatles also have reason to be grateful to Epstein for helping bring them from a minor British club act to worldwide phenomenon.
I erred anyway, getting Epstein confused with George Martin. Like that other band sang: ‘What a drag it is getting old.’.