Again...Fredo, stupid as he was, would probably have known his brother well enough to know that you can't 'scare' Michael Corleone.
There had to have been some other way he helped Roth. But exactly how is never, ever defined. Therefore it's a hole in the story, always HAS been a hole in the story, and always WILL be a hole in the story.
Unlike whether Fredo knew when he was about to die...which he did not.
And speaking of Ann (you brought it up, I didn't) Coulter...I bought the book tonight.
Not that she needed MY help, since due to the publicity it's alread #1 on NY Times Best Seller list.

Apple