To congratulate your friend on her new babies, first we need to translate the Filipino sentence into English. What she said means: "My pusang (referring to a cat) is about to give birth to five kittens." So, it seems that your friend is expecting her cat to give birth to five kittens. You could congratulate her by saying: "Congratulations on your upcoming little bundles of fur! I can't wait to see pictures of those five adorable kittens!"