According to the various Wiki pages about the band and its members, Malcom is permanently retired and suffering from dementia. His nephew Stevie Young (who apparently bears a striking resemblance to his uncle) will be taking over his roll.
Here is a 11-year old kid on german TV who masters both recognizing any given AC/DC song after 3 seconds and playing guitar like Angus. And he gets to meet the man himself as a gift and a signed guitar! Can't get much better