Those hour meetings act as a crutch that drain or energize us and falsely trick us into thinking we've done something productive.
Those 12 hours could have been spent differently to acheive the same or better results if optimized time management matters but I don't believe they do matter in this case. This person is fueled by the meeting (he leaves the meeting stronger) and by shortening his day he would never fully be in a zone.
One of the tricks to good leadership in my opinion, is running interference with my leadership or leadership from other parts of the organization, when they try and create new projects or otherwise divert resources to something that isn't a priority. It's a big part of my job to take these meetings so that the core teams delivering value don't get tasked or bogged down with them.
Meetings aren't going away, and in most cases these are requirements coming from outside of me or my team. Part of the trick of leadership is deciding what you can say a hard no to and not even engaging, what you need to do a soft no to by taking meetings (sometimes useless) in order to maintain good relationships, and then for things that are important but would cause new work, to do a lot of work at the leadership level ahead of new tasks impacting teams so that you can help them maintain their velocity.
Sounds like the exec needs less to be in those meetings and more to be aware of the agenda and high level action items from the meeting.
Or more likely to better clarify the expected outcomes with the localized manager or director and get the impactful/abbreviated action items every "Sprint".
Those 12 hours could have been spent differently to acheive the same or better results if optimized time management matters but I don't believe they do matter in this case. This person is fueled by the meeting (he leaves the meeting stronger) and by shortening his day he would never fully be in a zone.