In my opinion, the boss is simply angry because of his own brothers addiction. Angriness is a powerful emotion to hide hurt and disappointment without trying to admit these feelings to yourself or others. Admitting can be hard sometimes because it might mean that someone might perceive you as weak, especially if you are a man. Although it all depends on the environment one been raised in.
This video is only controversial because of the tone that it is being used to address someone’s addiction. As someone who had a drinking problem, I know how shameful it can be and someone telling you that you are peace of shit doesn’t work. Addicts already have low esteem.
I am not saying that the guy shouldn’t get fired but he shouldn’t be hired for the purpose of wanting to expose his addiction and shame him, that is cruel.