This is an extreme bummer, but considering his health lately, it’s not like I didn’t see it coming.
AC/DC (or I should say Angus, since he’s the only one left) really needs to take the classy way out to respect the band name like Led Zeppelin did, or we’re going to wind up with yet another money-grab tribute band like The Who and Boston, for a few examples.
A lot of people don’t realize it, but Malcolm was the backbone of AC/DC, not Angus. He wrote almost all their songs and also handled their production work, among many other things. IMHO, without Brian Johnson and now Malcolm, there’s nowhere for the band to go but down. That would really be a damned shame.