This lady is a train wreck, and her life is a manifestation of that, including her impulsivity with respect to pets. My hunch is that she has an underlying psychological disorder and needs some sort of counselling. "Telling her off" wouldn't be a very productive thing to do.
I know it doesn't make it any easier for you though. For your own protection, you probably need to distance yourself from her, thereby distancing yourself from the outcome of her decisions (namely, the pets). That little cat will do just fine: after all, it survived that crazy household!
