Give an inch?

[Greg Mitchell]

Have tenants, man and woman, who have had a falling out over finances.   Apparently she doesn't help him pay any bills, he has to pay everything and she's worthless, etc.  

In our lease, there is a $25/day late penalty.  He's asking for no penalty 'this time' because he's short until this coming Monday, supposedly.  He's also saying he's trying to get rid of her and have an old friend move in with him who will share bills.  

Not sure what to do...any advice for a newbie? 

TIA, 

GREG