That had to hurt. Cats turning on you in any way left a lot of trust issues behind, he knew that well from Nala, and a sibling must be even harder.
I'm sorry. he mewed sincerely, his tail moving upwards as if to rest on her shoulder before he yanked it back down. That might not be appropriate given the situation.
If you wanted you could come and try living with a couple of cats I live with. Pit mewed, his voice neutral and lacking in urgency. If she chose to, he wanted it to be her decision.
Only to see if you want to now, or if you need more time. he added, trying to keep it light, not forcing. @
leopardstrike4