All else aside, this would make for a pretty amazing answer to the "So why did you leave your last company?". I can't imagine the loyalty inspired by this type of "treat my team right or I'm out" mentality.
"I left because I was incapable of persuading management of the effectiveness and importance of my team and its contribution to the overall enterprise."
"Wow, don't you think you're being a little hard on yourself?"
"Well, they gave away my team's bonus to another team, despite my objections."
"That's unfortunate, but that still doesn't really explain why you left your last company."
"Well, despite the clear signal they sent when they took away my team's bonus, I didn't get the hint and completely misjudged my importance to the company. See, I painted myself into a corner by giving the executive team an ultimatum."
"Hmmm, yea, not very wise, you probably do suck as a manager."
It doesn't mean you suck as a manger that you don't get what you want. You never get all of what you want. I can only imagine someone saying that has no experience as a manager, or has been lucky and not found themselves in difficult circumstances. What sucks is if you don't even try to advocate appropriately for your team.
Would it be amazing? The people doing the hiring would be his managers.. not the devs he would be managing. They're exactly the people who may decide to take a bonus from his team if he's hired. And telling them that if they don't do exactly what he wants, he'll leave at a moments notice.. isn't a good answer to them (or really at all).
Someone will have to deal with this issue.. either him or the new manager. His job is to handle issues like this.. quitting the moment he runs into a problem is not a sign of a good manager.
"I left because I was incapable of persuading management of the effectiveness and importance of my team and its contribution to the overall enterprise."
"Wow, don't you think you're being a little hard on yourself?"
"Well, they gave away my team's bonus to another team, despite my objections."
"That's unfortunate, but that still doesn't really explain why you left your last company."
"Well, despite the clear signal they sent when they took away my team's bonus, I didn't get the hint and completely misjudged my importance to the company. See, I painted myself into a corner by giving the executive team an ultimatum."
"Hmmm, yea, not very wise, you probably do suck as a manager."