My sisters dog keeps trying to eat my kittens

My sister (28F) has a dog with the highest prey drive I’ve ever seen in a dog and that dog has small dog syndrome and bad food guarding behaviors. We paid for training classes and it didn’t do much, which sucks because her dog barks non-stop and bites/growls at people. Don’t get me wrong, I don’t think she should be put down or anything but I do want my sister to not just leave her dog at home all day. This dog will stalk by my door and look for opportunities to run into my room to get the kittens. And I know for a fact she wants to eat the kittens because we first let her see the kittens while they were in a cage just as a small introduction and she immediately went into predator stalking position and that’s when I KNEW this dog was hungry for baby kittens (these kittens are also small for their age (1 month) so they look like easy game).

Anyways I keep asking my sister to try her best to keep the dog away from my door because one time she managed to run in (she’s a small dog with small dog syndrome) and chased one of the kittens while barking extremely loud all the way down the hall. The kitten barely escaped with its life because it hid beneath the couch which the dog was too big to go under. My sister refuses to discipline her dog or even keep her in a roomy cage/room while my sister goes out. She claims that dogs weren’t meant to be locked up and I know that but my kittens lives are actively at danger and she doesn’t seem to give a single shit 😃anyways thanks for listening to me rant and let me know how I can reemphasize the safety of my kittens in a way to get my sister to finally listen 😍😝oh and advice on how to get the dog to understand that my fur babies aren’t food. Thanks xx