Eddie isn't going to be a fire fighter in El Paso. Forget the fact that he only gave Bobby the bare minimum notice before leaving and doesn't have a referral set up. He's walking away from more than just Buck and the 118 fam, he's walking away from his entire identity outside of being a *Dad*, and that includes being a firefighter. He's giving it all up, everything except Christopher. Partly as a form of self-punishment, and also because he thinks if he can be all-in on that one thing, then it can be enough. He can make it enough, because Christopher is his number one, and he hurt Christopher and needs to make it up to him, and that's all that matters right? Definitely not Eddie's happiness, that is the LAST thing that matters, in a world where Christopher isn't part of his life.
So Eddie gets an easy-to-get job that requires a strong body and few qualifications... construction. Or some similarly blue-collar job that doesn't require a skilled trade license. Maybe there's an accident or emergency at his jobsite that requires him to remember a bit about who he really is. But it won't be enough.
He'll start working on his extreme fixer-upper of a house *that Buck warned him about*. During the process, maybe he'll meet up with an old friend or old bully or someone he used to know. Maybe it's a contractor he's hired to help fix his house up, or maybe someone at his new job. But the point is, this person used to be all toxic masculinity and machismo, just like he was taught to be. But now, he finds out they're gay and have a husband and kids and are HAPPY and he'll ask them what happened? What changed? How did they figure it out? And this person will tell him a touching story of friendship, partnership, and choosing love - and everything they tell Eddie reminds him of Buck. The gears start turning in his head. But he isn't ready yet. Things aren't fixed with Christopher yet. He can't choose Buck until he has resolved things with his son. But maybe he's on the path to knowing what he wants, at this point.
Then - a disaster. Eddie's house is destroyed in a way that allows him to walk away with no lost investment or long term commitment he can't get out of. My guess? An electrical fire, because the house was so run down - and Buck WARNED him it was too run down. Regardless, the house is destroyed but Eddie will recoup his money through insurance, and now doesn't have anything *physically* tying him to El Paso anymore.
He will move in with his parents because he has no other choice. Tensions will RISE, and he will be confronted by (and have the opportunity to confront) his past. There will be an argument with his parents, and Christopher will overhear and step in to defend his dad. He finally gets an idea of what Eddie grew up with, why he is like he is and how different his grandparents were to Eddie than they are to him. This will spur a heart-to-heart between Eddie and Christopher where they FINALLY reconnect.
But this time, Eddie just isn't the *dad* who is strong and doesn't show any weakness. He will be human, vulnerable. Honest. And through Chris, he will get forgiveness, and finally find that he can forgive himself. This could also be where he admits his feelings about being away from Buck to Chris, and Chris urges him to go home to LA. Either they go back together, or Chris asks to finish the school year in Texas first - but promises to actually call and talk to him now, so Eddie won't be missing out on his whole life like he felt like he was before.
Eddie will return to LA whole and healed and ready to go after what he needs to make him happy. He will understand what he needs, and what he doesn't need. And he will know he needs Buck.
And because Eddie never tells anybody anything (and despite all his growth he's still EDDIE) rather than calling first, he will just show up on Buck's doorstep one day unannounced, in a parallel to the door scenes we had in 8x09 and 8x06.
Just watch. It's gonna happen. Especially Eddie's house getting destroyed and him recouping the insurance money. And if it does just remember me and my fellow conspiracy theorist @dana-duchovny told you first ;)