Well, then, wrestling has apparently some of the most nuanced, humanistic writing in fiction. Shit, I had no idea what the hell I was missing out on, I'll get into wrestling right away.
No, Vince's characters may be pretty out there in the sense that they accomplish big things with strong personalities, but I've met people who I'd believe were fictional if not for the fact that I see them in life. I had a roommate who I can only describe as a Tony Stark that happens to not be interested in inventing machines, I'm personal friends with a guy who excels at so much, I'd almost call him a mary sue, I've met a guy who was so desperate for friends that he reconciled with people who shit in his bong because he asked them not to make fun of him so much over their league of legends games, and I've met a girl who I can only call a female Sherlock holmes, and a girl who is a disney princess in personality. Maybe I'm unusual and just have met very interesting people in my life, but people who have big, almost unbelievable personalities...they exist. They're real.
But don't take my word for it. Look up Jenny Lawson's books where she talks about her life and try to wrap your head around that she is a real person and not a very well written comedy skit. Look up the stories about Alan Moore. Theodore Roosevelt was fucking RIDICULOUS. Arnold Schwarzenegger is a body builder turned actor turned politician. What is Donald fucking Trump if not the craziest, most unbelievable presidential candidate that you'd laugh off in a cartoon for being too unrealistic? You don't have to look far to find surreal, incredible people, they make their mark on the world all the damn time.
So yeah. Vince Gilligan writes nearly unbelievable people, I'll give you that. But they key word here is 'nearly'. Because when it's all said and done, they feel very believable.
And while I've met some pretty extraordinary people, I can't say I've ever met someone who had a healthy relationship with their parents, but was apathetic to the idea that they weren't as loved as their sibling. I wouldn't call being upset about that irrational at all. That is a shitty thing for anyone to feel, though it's unclear if that's truly the case (obviously chuck feels it's so, but his mother could have said his name for any number of reasons. She was dying and delirious).
And yes, that's exactly what he's mocking. His mother died, implying she cared about Jimmy more than him even though he's the one whose obviously more upset at her passing, and he's taking it personally. There's no way to seperate "Haha, what a tool for feeling resentful toward jimmy just because his mom didn't acknowledge him on her death bed" and mocking him for his grief. The entire state of grief involves being in a vulnerable emotional state. Saying he's a tool for taking what she said personally is literally waving away his entire emotional condition and mocking him for that is literally exactly what I've been getting at this whole time: people are refusing to empathize and understand his position out of a hatred for the character.