I think the play is to really try to get him out, rather than inheriting him, so I'll just plan to extend the date for as long as they need, and plan my living situation around that.

Not that there’s anything wrong with El Paso just anecdotally, based off my neighborhood, I see a lot of frequent rental property turn over and a lot of for rent signs out for an extended period of time. 

If he is dependant on his brother he has a major life issue problem that can extend into his personality.

The invitation is extended to you as well!

Next time, before you agree to extend a month, insist on a walk-though to determine if the place is in good enough condition to show.

This land would be suitable for mobile homes, RV's, or other housing and city utilities could be extended from my property.Realizing adverse possession is a long term process with risk, fencing, maintenance, taxes, and the associated legal hoops - are there any other "gotcha's" I'm not considering?  

For commercial your build out cost could be lower and your exit motion is similar w/ apartments but again you could have much higher initial vacancies.Financing wise if it's possible start contacting private money, otherwise you can get construction loan, and try to extend to a conventional loan later.

The home should have gutters throughout, and downspouts extending 4' to 6' away from the foundation.

In NJ, a landlord cannot refuse to renew or extend a lease or month-to-month just because they feel like it. 

In the last 20 years I am confident there are more areas that have ceased to cash flow (areas like Detroit if purchased near 2008) than there have been rate issues refinancing or using ELOC to get appreciation out of a property (because there have been no significant rate issues refinancing in the last 20 years as long as you qualify for the refinance (i.e. are not over extended)).Anything is possible but what you point as an issue has not been an issue in a long time but purchases less than 10 years ago that cash flowed have ceased to cash flow (not in all areas but it did get some expert/experiences investors: Ever hear of Mike Butler?