Considering WoW caps at 70 it was more than likely the push from 70 to 73 that killed him. Soon to be Dead Gamer: "Why iz I notz lvlin'?" Voice in Soon to be Dead Gamers Head: "Because you don't want it bad enough"
All that I can say it that he'd better have hit at least level 70. I mean I personally wouldn't be totally satisfied unless I hit 73, but could you imagine dying at level 54? 70 I could live with. Or die with.