Complex sentence: McVay's grandson, Sean, is a football coach in the NFL who became the youngest head coach in league history at the age of 30, after he was hired by the Los Angeles Rams in 2017.
Split into simpler sentences: McVay's grandson, Sean, is the head coach for the Los Angeles Rams of the NFL. He became the youngest head coach in league history at the age of 30, after he was hired by the in 2017.