I find Artie's character to be less than ideal. It's not clear cut. I've puzzled through some of the issues at my blog
Two recent TV shows that dealt with disability in humorous and insightful ways are "My Name Is Earl" and "Southpark." Probably the best episode for Earl is "Cost Dad the Election" costarring Tracy Ashton as Didi, a reoccurring character, and Cameron Clapp. Both are amputees. Also good is "Killerball" which involves wheelchair users.
"Southpark's" most famous disability episode is "Killer Krips" satirizing Christopher Reeve. The disabled Timmy and Jimmy are regular characters on the show. The episode, like most Southpark shows, pulls no punches and some might find most of the episode offensive.