It sounds like a hoarder situation where they can't see what they're doing is really unhealthy for the animals. Cats get airborne respiratory infections quickly and stuff spreads easily around where there are lots of cats. She needs to keep the place clean. If it were me I'd probably forget the merciful approach and place a consumer complaint to the better business bureau or to a local spca if there is one where you live. It sounds like this is the tip of the iceberg of one of those facilities that ends up on some animal cops show after years of investigation. Something needs to motivate her to get help or get out of the business.