This may not be a popular opinion, but a wise person who had built up their own small real estate portfolio once told me to never be over-leveraged. Their advice was that my income from other streams needs to be enough to cover the mortgage and related expenses on the rental units I owned. They also taught me the value of having multiple income streams. And never 100% finance a rental unit as that is very risky. I feel bad for the landlord, but it sounds like this landlord took big risks, built his empire up too quickly...and ended up losing.
I'll agree with your buddy when starting out, but if you really want to FIRE with real estate you are going to need to have a lot of properties. As your portfolio grows you will become more comfortable with debt and the portfolio should be able to take care of its self. However, up until 2020, I never imagined a scenario where potentially ALL of my tenants would stop paying (FYI I only have one who is paying very late each month). If all my tenants did stop paying, i have a ton of cash to float this, but it would hurt seeing the money go out each month. That said, investing is risky, If you don't want risk, buy an annuity.
If the investor in this article can hold on, maybe sell the Benz and buy a 4k Corolla to float a few months. In 5 years I'd bet he will be in a fine position to buy that Benz back. Which I would never drive when picking up rent checks. That's just poor optics. I have a classic beater I use while visiting my rentals (2006 Acura MDX with dents in the side panels). Man, I need to get a truck, I have trashed that car.
Main thing i got from this article, This is what the 1% rule buys you.