Your friend had five new kittens be born alongside your cat's litter. Therefore, you can congratulate her on the growth of her family, including four furry babies and a healthy addition to the clan, one kitten from her cat. It seems like they both have a bundle of joy to celebrate, making everything twice as lovely and interesting in their lives. Enjoy the new arrivals and continue to support your friend in her journey as a proud mother of these adorable creatures.