That fan's name is Rob Ager, and he's put together a pair of videos that carefully and exactingly dissect Carpenter's excellent survival horror flick. Everything from seemingly incidental sound effects to costume continuity is included in the analysis, with the ultimate resolution being that, yes, Childs had been assimilated by the alien entity by the end of the film, and that MacReady roasted him with a flamethrower shortly after the last shot.
What do you think? Has Ager proved his case? Would you have torched Childs?