I have been warning about this for years....never never never apply dog products on cats, and never never never listen to anyone who says it's ok to do so (this happens way too often on the net). I hope the owners have learned a lesson.
I hope it wasn't Hartz, their products are known to cause various adverse reactions, including death and particularly in cats. ALL permethrin based flea and tick products are potentially lethal to cats, they ought to be banned. But of course, the EPA has been sitting on their duffs for years and allows to be strongholded by companies like Hartz, etc
The babies are in my prayers, Tambrey, if they receive agressive treatment, they may in fact make it, I'm pulling for them.....