Solving the Biggest Mystery of the Fast and the Furious

Something about the Fast and the Furious franchise doesn't make sense. I'm not talking about the team's sudden development of incredible fighting skills, an international network of contacts, Dom's ability to fly, Tej's ludicrous hacking skills, or even the timing of Dom's son's conception. That's all fine. The mystery for me has always been what happened to Leon. Remember, Leon? He's the jacked white guy who is part of Dom's crew in the original Fast and the Furious. Not Vince. The other one. You know, he's there doing stuff in the background with Jesse and, when the final truck hijacking goes wrong, Dom tells Leon to go back for Letty (who rolled her car or something). Leon is neither seen nor heard from again. He's not in any of the other movies. He's a member of la familia one day, then he's just gone. We don't even get a courtesy explanation like we had for Brian (Paul Walker) in F8, something like: "No, we all agreed not to bring Leon into our further adventures." The most logical explanation is that Leon was allied with Dom in a covert war to save America.