Breaking Bad came out in the late 2000s and this was a time when being "politically incorrect" was epic - and by politically incorrect I mean just punching down and being hateful. Slurs for disabled people were used without any meaningful pushback, and at least in my experience, kids were happily reciting lines from South Park and Family Guy at school and mocking kids from SpEd classes. These things still obviously happen today, but now there seems to be more criticism of when it happens and even the "anti pc" crowd will hesitantly shut up if called out.
Anyway, Walt Jr. has cerebral palsy, but unlike much of the media of the time, he isn't the butt of the joke (aside from that one scene in the store but the bully got his ass kicked) or made cynically by someone who doesn't care or know anything about the disability to get a cheap emotional response from audience. Obviously he doesn't have an identical life to someone who is fully able bodied, but overall he's just a kid with his own angst and goals who just happens to be different. Sometimes he needs assistance, sometimes he doesn't. Sometimes his parents struggle to relate and help him (both for his disability and puberty in general) and that's just life, especially for a lower income family that doesn't have access to all the resources or free time to discuss problems.
I'm not surprised that they made :dean-malice: racist because he's a DEA agent, but rewatching it I'm surprised they didn't make Walt Jr. a caricature because most people wouldn't have bat an eye.
For me, that was the redeemable side of the Rome show that made it bearable to me, even if I'm generally not fond of the "prestige TV" format. Lucius Vorenus spent almost the entire run of the show just trying to be a good upstanding Roman no matter what happened to him and his family, and he kept fighting on the losing of side of many conflicts and kept on doing it until it was the death of him. Titus Pullo was a bit like that too, if a few shades more complicated.