I would say once areas start to get saturated with tenants they are on a down hill trajectory and will just erode from there. 

Basically, if they are on the downhill side of life with lots of problems, no job, bad record with the law, etc. they are not likely to land a decent job and work their way out of the abyss.

As I am sure you can guess, this is not the only issue with these two and the issues seem to be gaining speed as they continue to go downhill, so I decided this is where my limit is, as I have really taken the time to talk about it extensively with them.

Sometimes however, they simply are in denial when their business is running downhill, and they make things worse.

Frankly I’d look to do both 5 years getting investment up to 2-3k a month and the heloc and you could be in a different place entirely because it starts to become a boulder rolling downhill. 

I used to like them but they've really gone downhill.

Get that snowball rolling downhill.

Up until early 2020, we had been fully rented with student groups at market rates, but once the school shut down for the pandemic and the area went downhill we have been unable to rent it to any groups (student or qualified non-student groups) even at steep rent discounts - it does not help that there have been multiple carjackings and a murder on our street during lockdown.  

An experienced investor told me to be careful with older houses, as they may give good returns the first year, and after that it may be all downhill, as repairs eat up potential profits.It's great that he knows the area, but there are lots of areas that are bad news now which weren't when 'we' grew up there.Is this your first investment?

There's up hills and down hills and obstructions to surmount but just plodding along and enjoying the beauty along the way eventually gets you somewhere.