I guess in some ways I listened because when I dated a tradesman I worked with them to learn and still have friendships or family in every trade except plumbing.

Personally, I'd rather not chance ruining a friendship so I wouldn't mix the two but that's just me.

Your concern about how they will leave the home backs up my assumption.This "friendship" has already cost you thousands and probably created a lot of friction and stress in your home.

Not to mention the friendships and business relationships i formed thanks to BP. 

There is a high probability your friendship will not last. 

Really, you have to put the friendship first.

@Bill Piker, it is a business not a friendship.  

Guys, all good relationship that matters is how good you keep your checking account and your credit card with but none of this personal friendship with the people inside matter.

Perhaps avail yourself as a free intern for a period of time to help the person out while all you get is the information from doing it (you can also make good friendships that way). 

They are not your friends/good terms, they are using the friendship to prolong it....it never works out.First sign was when they were pushy trying to tell you what to do with the other tenant...your the boss.