Of course he gets to tell his story. It's his to tell, and he clearly feels the need to tell it. He should write the book if he wants to.
What he doesn't get to do is to control the reaction to the book, either by the press, or the readers, or his own family.
I suspect that there will be some self-reflection, some self-pitying, some juicy material, and some material that will make it impossible to ever be fully part of his family again.
It will probably be well written—the ghostwriter is good and has decent prose control.
The problem is, of course, is that all he has to offer is his own narrative. His work will never be lucrative enough to support his lifestyle. And he's decided the lifestyle is more important than his privacy or his peace of mind. It's a fair choice, but it certainly is a choice. So he has to sell parts of himself, and his secrets and private thoughts, off one by one.
Personally, I couldn't live that kind of bankrupted life. It seems awful to hate the thing that you rely on for more money rather than pushing forward with your own life and setting your own terms. But he wants the money, and he wants to settle scores, and that's reasonable enough, I suppose. And he's not going to become more interesting as he ages.
It seems all very hollow and vapid to me, and a sad acknowledgment that his feels his past is what is valuable about him. But he certainly gets to make that choice. I just hope he can stomach the consequences (not familial, but the license it will give people to make his private life public fodder).