I can't tell if he SAd him or just abused him. I'm guessing from the type of story it is it's sadly SA but I don't really understand the motivations of the character from being angry and the wife for killing his brother and him feeling like the children were in on it to r*pe. ( ̄へ ̄). I almost wish there was a debrief after each few chapters but I'm sure the next few will pretty much explicitly say it.

Holy shit I'm sick to my stomach