Catching up on this, Brisket. For whatever my opinion is worth, and based on what you've posted about your kids' journeys so far, I'd say they have a pretty good knack for finding their own way, even with a little pat on the rear from Mr. and Mrs. Brisket, so I say let the boy go fight some fires. He feels compelled to serve, and this is what is pulling at him. Hell, he might fulfill some European hottie's first responder fantasy. Grad school will still be there down the line, if he wants that. Not sure the law is his path, but I had a career cop in my 1L class.
If I have any regrets in my life, one is that I didn't join the Marine Corps like my dad. I mean, I don't want to change anything about where I am and the path that I took to get here, and even a minimum tour of duty in the Marines would have wiped all that out. But in fantasizing about another life, I would have liked to have served my country in that capacity, even if it meant an overseas deployment during wartime, like one of my high school classmates experienced as a Marine.