Eddie Diaz Is Bad With Money And It's Perfect
You know what I love about this show? They seed character flaws. Not every negative quality gets a plotline or becomes a thing. Sometimes they just toss a couple lines in here and there, so if they need something later. Case in point: Eddie and money.
Eddie is an impulsive, if not reckless, spender. In season 2, he treats the cost for Chris's private school as a non-factor, as if it has no value. He lavishes Chris with whatever he wants, something Shannon calls him out for. In Season 3, he buys a truck on a whim. Yes, he had extra money from the fight club, but he still made a major purchase on "fuck it, it's hot". Throughout the seasons, Eddie buys whatever he wants at the drop of a hat. And yes, it's TV, but the other characters still mention money, budgets, et cetera. Eddie never does.
So him spending every penny on a fixer-upper in El Paso when he'd been content to rent for years in LA fits him perfectly. He just doesn't handle money well.
And again, I love this show, because they those throwaway lines of reckless spending tie perfectly into Eddie's backstory. As we've seen more of Ramon and Helena, we've seen what kinds of parents they were. Passive-aggressive, guilting people into things, but also the kind who were very focused on how they looked to other people. The trophy emphasis? That's what that is: being more concerned with other people's views than their children. And that kind of parent is absolutely the kind that treats money and things as proof of love.
Eddie didn't need to join the military to provide for his family. It would have been harder to go to college or trade school and work, and would have required leaning on family for support, but it would have been possible. But Eddie didn't. He enlisted to support his family, because he was raised in an environment where money and material goods were the proof you love someone. It's why his reupping worked as an excuse: he was providing money, the strongest proof of love. We see in Season 6 that Ramon and Helena don't rank the presence of a parent as much as a high income, and in flashbacks, their arguments that they can provide a better home for Chris is rooted strongly in money and things.
Circling back to Eddie's military service: a decent number of enlisted are shit with money. I get this from my dad, who was a JAG for 22 years (8 active duty, 14 national guard). He helped a lot of young servicemen through debt and bankruptcy issues. The pattern he saw was this: men who enlisted young and didn't have family's on-base tended to have poor financial control. Policy at the time (80s, might have changed now) was that for a length of time, at least Basic and possibly beyond), a service member didn't get their full pay. Half was paid then, and the other half deposited into an account they could access after graduation. A decent number of those young, single service personnel would then see that big chunk of change and then blow it, typically on sports cars (Dad did work on a lot of repos).
Eddie enlisted young. Young is key, because these are the people who went from their parents' home to basic training. They never had to manage their own money, set budgets, pay bills, and the military (at least back then) didn't teach financial literacy. All the money of an adult, with far fewer responsibilities.
The other part of that pattern, though, doesn't seem to fit. Eddie was married with a kid, not single. But the reason it was single service members was that they lived in the barracks, and when you live in barracks, you don't have to pay rent or utilities. We're never told that Shannon and Chris lived on base with Eddie when he was stateside. We only ever see them staying with Ramon and Helena. (No wonder Shannon broke.) This means that Eddie likely lived with his parents and/or on base, in barracks, eliminating his biggest expenses while likely remaining eligible for housing and food supplements for his family.
Thus, for the duration of their marriage, Shannon and Eddie's finances probably went thus: Eddie deposited most of his paychecks into an account Shannon could access. There was likely an amount set aside for fun money for Eddie, but he would have very few bills while on base or in-country. Instead, Shannon, the accountant, handled their money. She did the budgets, paid the bills, clipped the coupons, et cetera. Eddie only had to buy things he wanted.
And that mindset never changed, even when Shannon left and Eddie had to take over the money. At no point had Eddie ever had to sit down and learn to handle money long-term. And he still hasn't. He gives Chris whatever he wants, or even what he thinks he wants because he thinks that's love. Chris has to tell Eddie to save his money in Season 8, because Chris, at this point, has more financial sense than his father.
Proof of that: All Eddie's savings went to the down payment on a fixer-upper. I took a quick hop over to Zillow. El Paso is not a super expensive city to buy in. Lots of fully renovated homes for $175-300000. The down payment on a $300000 house can vary, from as low as $9000 (3%) to as high as $60000. The average rate is 8%, which is $24000. But Eddie didn't buy a $300000 house. He bought a fixer-upper. So lets cut that by a third to a half. That's $12000- 18000 dollars. Eddie, after two decades of working (2 6-year tours + 8 years LAFD), got wiped out by less than $20000 dollars. And yes, medical bills, separation costs, cost of living. But having that little savings, after that much time, after Shannon's estate and her life insurance (he was still her husband at the time; he'd get everything), and never giving an indication of living paycheck to paycheck (again, he bought a car ON A WHIM)? That's not just bad with money, that's pathologically bad with money. I hope Shannon's estate got placed in a trust for Chris or he is beyond fucked when it comes to college.
TL;DR Eddie is brain-meltingly bad with money, and Buck should handle all their finances.