Based on the German text your friend shared, it appears she is referring to Lisa's cat (die Katze = the cat) giving birth to 3 kittens ("Ihre Tatze hat 3 Junge bekommen" = "Her paw/cat had 3 young ones/babies"). So to congratulate your friend on her friend Lisa's new babies, you can say something like: "Ja, ich habe es gesehen! Wie süß, dass Lisas Katze 3 Kätzchen bekommen hat. Ich kann verstehen, dass du auch gerne eine Katze hättest. Vielleicht kannst du Lisa ja manchmal besuchen und die kleinen Kätzchen sehen?" Translation: "Yes, I saw it! How cute that Lisa's cat had 3 kittens. I can understand that you'd also like to have a cat. Maybe you can visit Lisa sometimes and see the little kittens?"