My 12yo son had a difficult time with jokes, he loves cartooning he tried to make comic books and they didn't make sense. Since his siblings also love jokes, old comedies etc.. they would explain jokes to him, believe it or not watching I love Lucy and Marx brothers helped quite a bit .
My older children (14,15) would read jokes aloud and if he didn't get it they would explain the play on words and we would get Charlie Brown, Over The Hedge and Calvin & Hobbs etc.. and he would read them through and through..when he didnt get something he would say "this is a joke because... is that right?"
...this has been going on for a couple of years and I can tell you he has become very witty, things still elude him every so often the the improvement has been extraordinary...he makes such funny comic books
actually he is now making new comic book characters that have Aspergers :)
disclaimer: we are not always fond of Calvin & Hobbs, sometimes Calvin I just too much as is Garfield etc...but we oversee their reading and sometimes we just ban them when he gets too obssesive :)
hope this is helpful :)
blessed day
Clara in Miami