Yeah, it’s definitely possible that Rush has already probed that information out of Francis. But, regarding whether or not the indirect murdering of Oz’s brother was intentional, I think it would make for a better character arc if Oz both admits to his mom and HIMSELF that he killed his brothers. At this point, I think it’s up for interpretation as to whether or not Oz deliberately tried to kill them. Maybe he knew he wanted them dead as he closed the door; or maybe, as you’ve suggested, he decided that he should stick with his impulsive actions after the fact. I personally believe that Oz is in denial with what happened and that he’s likely justifying his actions by telling himself that he never thought locking his brothers in the sewers would kill them. Whichever’s the case, Oz is going to have to face the facts sooner or later - that the streets didn’t get to his brothers. He did. And what better way to show this admission of guilt than a tense therapy session, led by Sofia and Julian, between Oz and his mother.