According to vetex (and AO as you’ve pointed out), landon does indeed die after durza is beaten and chaos ravages the seven seas. But as others have said, the webcomic isn’t canon so who knows if sheep will adapt this part (maybe it will be changed in the webcomic or maybe it won’t even get to that part).
Though sheep has worked pretty hard to keep the webcomic pretty accurate to the outlined events of AA, so it ain’t looking good for our boy 