Complex sentence: After graduating from Coventry High School in 2005, he relocated to Los Angeles, California, where he became personal assistant for his cousin, Rob Dyrdek, which in turn led him to become a well-known reality star on the MTV channel.
Split into simpler sentences: After graduating from Coventry High School in 2005, he relocated to Los Angeles, California, where he became personal assistant for his cousin, Rob Dyrdek. Which has led him to become a well-known reality star on the MTV channel.