Complex sentence: His father Harold (1919--2008) was born in Brockton, Massachusetts but grew up in the East End of London from the age of two, when his mother left his father and returned to the country of her birth.
Split into simpler sentences: His father Harold (1919--2008) was born in Brockton, Massachusetts. Harold Rosen settled in the East End of London at the age of two, when his mother returned to the country of her birth.