Sometimes I have to show clients the math for them to get comfortable with it. 

I'd love to shorten that for him a bit with REI or just make it a bit more comfortable when we get there. 

This gives much better diversification protection across geographies, asset types, strategies, investment subclasses etc. versus putting all the eggs into one basket.The downside is that it's not for everyone, and a person has to be comfortable with turning over control to someone else.

I am currently serving in the United States Air Force, so as a military member, I will be moving around during my career. 

You have to walk home, and feel comfortable.

Just make sure you’re comfortable with the interest rate if going either route.  

Through my studies, I met my current employer, who owns a construction company where I serve as the Sales Director.

@Grant Shipman, I will say, I have not explicitly seen anyone violate these rules (that I know of), but more commonly there are a lot of people who have comfort operating at the margins.I.e. compliance officers/attorneys that stop at the letter of the law may say: "investment manager X, you can advertise your company all you want.  

If he doesn't need the cash now, you could also negotiate a split you're comfortable with to get him the return you and he feel he should have at the point you refi when the balloon payment comes due. 

I can run and model numbers and am a CPA so comfortable with the finance side of things.