@Jacob Wathen, I'm glad you have more foresight than your parents, but I can't imagine how frustrating that must be

I couldn't help but feel frustrated as I explained that YOY, his home value was still way up.  

I can definitely understand that frustration. 

Seriously frustrating though.

Unfortunately it is not, this actually happened.I feel terrible that he is going through this and also frustrated that I cant take any action as I don't know who the culprit is. 

I can understand your frustration.

It's so frustrating cause it is unclear if I'll receive any payment at this point.

Try to avoid this again by screening very carefully for your next tenants and be sure they know that there is no wiggle room when it comes to paying the rent on time or taking care of the property.When we had to go through it, yes it was very frustrating and there were times when I was wondering why anyone would put themselves through it - at the same time , there is nothing more satisfying than developing long term positive cash flow while helping put a roof over a family.

That was frustrating for me to discover, myself (after the fact, of course.) 

As a property manager we here tenants say that they will with hold rent but this only happens when they get frustrated.