You don't need to understand why. He doesn't know himself or he could tell you. Quit trying to figure it out.
It is sufficient that he feels it is a choice he has to make to have a happy life. He may or may not be right about it. But, he has to figure that out for himself. If you need some kind of reason, that is why he has to make that choice right now.
Good job calling a friend. Stick to your plan. And, focus on your trip. Go buy party gifts for everyone. Make them a little naughty, lol.
