His book on Galante was excellent. He or the co-author tracked Galante's record back to his teens. Only missing piece was his time in prison.
I have not read the book, but a person who did said he claimed Galente used to torture people with acid a he killed them. If DiMatteo said that he is getting worse with his ridiculous stories.
I haven't read the book either, but why do you think Galante torturing people with acid is so unbelievable? There have been gangsters who could well call him a "softie" even if it's true. Just look at Filippo Marchese, Toto' Riina, Sam DeStefano etc. Torture isn't exactly unheard of in the mafia.