If so, you’re best bet is probably to hire someone separately to fix the problems to save the sale.

You need to look at the sale of duplexes close by to start formulating what they go for, then perhaps add a price adjustment upwards for price/condition, assuming other duplexes are old.

Best bet for you and them is for them to find a more affordable arrangement.

Try hitting up a agent and let them know what you are looking for and I bet they could have you a property that would work.

All of this info can be sourced from online platforms and articles, real estate investment meet-ups, and general networking with folks in the industry.Maybe studying all of this is unnecessary, but at the end of the day, the more you can perceive change in the RE space, the better you can adjust your strategy and criteria to profit in the market. 

They are adjustable and callable every 5 years. 

Yes, there are adjustments for the differences between the comparable sales and the subject property (your property), but they are relatively subtle adjustments because they are using "comparable sales".

Hi Nicholas,As a contrasting thought, consider that "diversification" only makes sense if you are allocating your wealth into several good bets.

And a HELOC adjusts, so while the payment is low right now, it will go up. 

I bet you like the equity gain for those 2005-2015 investments:)