I like the scene for three reasons. First, I like it because Walter, Jr.'s disability is always noticeable but rarely important to the story. Second, the scene is a reversal of a disability drama cliché … usually it's a non-disabled character telling a disabled character to "snap out of it" and "stop feeling sorry for yourself". Here, it's the other way around. Third, I like that Walter, Jr.'s argument works precisely because his Uncle Hank respects Walter, Jr. so much for his independence and way of dealing with his disability.
As an aside, the character of Walter Jr. is played by actor RJ Mitte, who does have cerebral palsy. In an interview, he says that Walter, Jr.'s impairments are a bit more severe than the actor's own, so that Mitte has to sort of go back to a time when he, himself, used to be more significantly impaired … walking with a bit more difficulty, and speaking with slightly more of an impediment.
If I can't find a way to include this scene in my collection, I'll be sad.