People tend to loose their shit when a parental figure who could only love or show approval "conditionally" is suddenly whisked from their life. That person made you feel like you were always one precarious step away from being that "bad person" they couldn't love. You believe your "default" identity is intrinsically BAD, so every bit of energy in life is put into NEVER having to experience seeing them ashamed of you. If that is your sole motivation in life, when that carrot on a stick is gone, what are you left with? You loose your shit. If you've never dealt with and worked on fixing that warped dynamic, even middle aged adults can become completely unhinged when their withholding or abusive parental figure finally kicks it. I witnessed it in my own father. Now that person can NEVER get that - all hope of "finally" being good enough is gone. So with the loss of the person also comes a totally loss of hope to ever feel accepted, and falling into a complete self loathing or "f*ck the world" nihilism. They project that rejection onto EVERYbody, even those who love them. Jimmy isn't screaming at Kim on that rooftop, he's screaming at Chuck, and will for the rest of his life .
(or not - the series isn't over yet!)