What are the odds that one light cycle (10-12wks 500mg test e or c a week) will prevent you from 100% recovering?

By recovering I mean:
Testicles return to 100% normal size
Sex drive is 100% prior to cycle

A friend of mine was running 750mg of sust for about 14 weeks, it was his first cycle.

He ran proper PCT, but he's been done with PCT for about a month now and he's complaining that his sex drive is not what it was, and his testicles are not 100% back to their normal size.

This somewhat concerns me, although he did run a pretty high dose of sust for a first time cycle, and he ran it for a while.

Has anyone ever heard of 1 cycle, followed by PROPER PCT ruining your sex drive forever?