I love the idea that Rui gets all his teasing abilities from his mom ꉂ (´∀｀)ʱªʱªʱª. I like the idea of both Rui and his mom being alphas while Rui's dad is an omega, which isn't traditional but fits Rui quite well. Both of them would be very excited to meet Tsukasa, they have seen the omega before because WxS sometimes meets at Rui's home, but they never got to “formally” introduce. They have seen Rui change so much since he met Tsukasa; seeing their pup taking care of himself and also so radiant when he speaks of the omega makes them happy as well, knowing that he has such a wonderful friend and that he has such a cute crush on Tsukasa. It's cute for them to see their pup, who used to be so lonely, having those feelings for the first time.