After going through the message, it seems your friend's friend, Lisa, has young children - specifically, three little ones as mentioned by the person whom it's being conveyed to. So you can congratulate her on the arrival of her three new babies. As for the person who wrote to you, she seems enthusiastic about both having children and owning a cat one day. Keep that in mind as well while addressing this matter. Nevertheless, make sure you proceed with caution, so as not to inadvertently say something that might upset your friend further.