Wtf was that I didn’t understand shit

From what I understood, it seems like the captain’s little brother was obsessed with him and so set this whole thing up in order to ”activate” his older brother’s sexual desire/sensations through tentacle rape? which had been turned off somehow by their father because he wanted a perfect son with no flaws. The plan was a success, but went a little too well since Kachanov and the captain ended up falling in love? or at least develop attachment. The younger brother ended up killing Kachanov, the subordinate, because he wants his brother all to himself I guess. So basically the story of an obsessive younger yandere brother?