Castro was not exactly great looking himself. His mom was pretty. Keith would probably look differently if not for the massive drug and alcohol abuse. He is the only guy in the Pirates of the Caribbean movies who needed no makeup.
As an old fat guy he looks just like you’d think, he looks like an old fat guy. Keith Richards, on the other hand, has always looked like he looks today, just with fewer wrinkles when he was young. Apparently Castro was regarded as quite the ladies’ man in his heyday, though.