They might also not have favorable lease terms.

So do yourself a favor and research your local tenant/landlord laws as well as any changes due to Covid more thoroughly.

Core PCE is the inflation indicator favored by Fed officials, and their stated target is 2.0%.

Investors usually do this when they are increasing the value of a property by a large margin, or if they can get private money terms that are much more favorable (like 8% with no origination fees). 

The good news is, I think your brother should easily be able to point out how one-side that lease appears (in the landlord's) favor if he wants the tenants to sign a new lease, and convince them that signing his lease is actually in their best interest.

Now, for the appraisal to come back favorable is the next step as well as the permitting.

Now if you bought 3 distressed tri or 4 plexes using rehab loans then BRRRR'd them all, turning them into clean/ safe/ decent section 8 rentals, you'd be cash flowing nicely, have all your money back to rinse and repeat, and be doing us all a favor by bringing up some distressed neighborhoods, not to mention providing housing to people who need it most.

Are the tax laws favorable for real estate investors?

This can be by working with smaller banks, using your current property as collateral, taking a HELOC out on your current property, negotiating favorable owner financing terms on the new property, etc...

Finding a favorable property where the numbers work is very very important, but also remember Brandon Turner's  wise words, "The first property is about getting in the game."