Responses
In chap.4, Shouma said that he always like Kyouchi 'all this time' which means before Kyouchi's confession. And for the divorce matter, maybe for him if his parents were separated the relationship between Kyouchi and him still remains the same as siblings. Shouma just hold back his feeling towards Kyouchi so that he can still be by Kyouchi's side.(this is from my view
You're right.
This is adorable but my question is did Shouma like Kyouchi before his confession or post confession?