The dude that works at the parts house where you get parts, is infinitely more intelligent than you but never really helps any situation....probably lives with his folks and is in his early thirties

A phrase to describe someone who is cognitively degenerating. Synonym of "going off the deep end". Can have varying degrees of severity.

Reference to the song "Hey You" by Pink Floyd. The line "and the worms ate into his brain" makes no sense in an otherwise linear and literal narration throughout the lyrics.