He should definitely get an oscar. If not for his role as the Joker than for his pure acting ability. It wasn't just The Joker as played by Heath Ledger, it was Dark Knight starring The Joker himself.

yes it is possible to win a oscar after death it is called a posthomous oscar,Brandon Lee got one for the crow as have several other dead actors.

i think he must get the awards...as awards r given for the work done by the person...as joker HEATH did awesome job...and he must get the award for his work...