In this interview, he explicitly says he is chief engineer at Spacex. He goes on to explain that this means all design decisions are stamped off by him, and thus any failure is due in part to him. Conversely, this means he signs off on all the successes as well.

Seeing as he’s the chief engineer and is intimately involved with the design process, why do people still say he’s: a brainlet, business man, doesn’t do any real work, etc etc