Relative of mine may or may not be going into military, they were telling me this

I've got mixed feelings on the matter. I spent four years active duty myself, until it messed up my left ankle to the point where I almost ended up in a wheel chair. At the time and many years after, I thought (honestly) that it was the worst mistake anybody could ever make, to volunteer to join the military. But now I'm much older and much wiser, and I see the "big picture". The "big picture" is, until you learn to invest, to make your money work for you....you will always be a slave to somebody else. Period. A successful investment program can be implemented with as little as $500 a month, or maybe even less. As long as you are adding to your portfolio consistently over time. With the power of compounding interest, just about anybody can get rich if they are patient to wait 25 or 30 years. I'm not talking filthy rich, but certainly independent to the point where you don't have to work outside the home EVER again, unless you want to. So let's say you are 18 and ready to join the real-world workforce. You know you've got to invest to achieve financial independence...or work yourself to death, always working every day of your entire life. How do you get the money to invest? It really doesn't matter. There are worse ideas than military service. Do that for 20 years, and then do contracting for another 10. That gives you 30 years for your portfolio to grow. BY then, you are about 48 and ready to retire. And you won't need a military pension or social security to lean on, either.
On the other hand, if you don't want to join the military, just work full-time at wally world or whatever. Live cheaply enough so you can put $500 a month into investing. I know guys who CHOOSE to live in a tent, just to do that. When you are young and healthy, the sacrifice can be worth it. You are earning your freedom.

My oldest nephew is also joining. I worry.

Just keep in touch with that relative of yours. Where they end up, it’ll really help them through the tough times to hear from you.
I hop your anxiety eases too.