Your friend's message says, "My cat just gave birth to five kittens." So, congratulations are in order for your friend's new family addition -- the five adorable kittens! Some common congratulatory phrases you could use are: - "How exciting! Congratulations on your new kittens!" - "What wonderful news! May they bring much joy to your home." - "The babies are so tiny and sweet. Best of luck raising them." - "Your kittens look absolutely precious! I'm so happy for you." - "Explaining you are welcoming 5 adorable new kittens to your family. Much love!"