I had one cat to deal with, imagine several. Stray cats, feral cats can be dangerous and who’s property are the using? If she feeds the cats, she should take them in and care for them properly with vet visits and such.
I’ve owned feral cats. They won’t harm the kids. They keep to themselves and other cats. The ferals I had would only come near me when I had food and then they would run off somewhere. Plus they don’t have a long life span.
He should call animal control.