I’m this whistleblower and then all of a sudden:

Since the death of his father and then his marriage in August 1997 to Francesca Tomasi – a former Metallica crew member – he had been swinging back and forth between on-the-wagon sobriety and on-the roadhell-raising, even after the birth of their children Cali (in June 1998) and Castor. Happy to play the gentle giant family man at home, away from home – not just on tour but on his frequent, all-male hunting trips – James was still the same short-tempered human grizzly he’d always been. When, during a short vacation during those initial months working on the new Metallica album, he found himself away for his son Castor’s first birthday hunting bear and drinking double-strength vodka on the Kamchatka peninsula in Siberia, a four-hour helicopter ride from the nearest small town – he finally began to crack. When Francesca then confronted him, threatening to leave with the children if he didn’t do something about his monstrously selfish behaviour, ‘That was the end for me,’ he confessed. The upshot was an eleven-month programme of rehab – ‘a nice little cocoon’, he called it. Not so nice to begin with, though, during those earliest, most painful days of recovery: ‘I realised how much my life was fucked up. How many secrets I had, how incongruent my life was, and disclosing all this **** to my wife. **** that happened on the road…Women, drink, whatever it is.’ Making a clean breast of things had a knock-on effect with the rest of the band, too: ‘Like I’m this whistleblower and then all of a sudden: “Er, wow, isn’t it terrible, honey, that he did that?”’ Yet, as far as James could see, looking back almost ten years later, ‘it was the saving part of Metallica, there’s no doubt. It had to come to an end a certain way.’ Tormented by the thought of losing both his wife and his band, he decided: ‘I’ve got to get it together or they’re both going to go away and then what?’
1. What does on the wagon mean here? 2. What does crack mean here? That James fell ill 3. Could you reword ike I’m this whistleblower and then all of a sudden: “Er, wow, isn’t it terrible, honey, that he did that[/b]?- Who is talking to whom and about what-could you please rephrase that. Thanks a lot.