The refrigerator is a favorite spot of some breeds.They will crawl through this powder and bring it back to the colony, if any.I would confront the issue honestly and directly with the tenant in a non-confrontational way.

Should I confront the daughter when she is there?

Instead of confronting their fears, they allow their fears to hold them back.Fear of failure, fear of losing money, fear of embarrassment, fear of starting over, fear of rejection etc.A lack of knowledge regarding real estate will intensify these fears, making it more difficult to manage.Often enough, many people take advice from people who failed in real estate or who have never had a successful career in real estate.

Surely she could just tell Bro to move on...or is she secretly not wanting to have confrontation with family.  

I have not confronted them yet because im not sure what is the right thing to do.These tenants are ALWAYS early (10 days) with the rent, although they do complaint about any little thing (even when visitors ring their bell by mistake) and are not the cleanest. 

Or should I, as amicably as possible, confront my current lender about it?

Since it wasn't put together well, now is the time to mitigate the situation as best as possible and not be confrontational. 

Makes me twice as quick to say 'no'... errr, I mean, "Sorry, I found a more qualified candidate" when I'm next confronted with something like this.

Very difficult to confirm and confront as there is ALWAYS MOLD.This mold was not visible.

And please know, I am asking legitimately with interest in the answer, not confrontationally as many people like to be on these forums.