Complex sentence: Biden's father had been very well-off earlier in his life, but suffered several business reversals by the time Biden was born, and for several years the family had to live with Biden's maternal grandparents, the Finnegans.
Split into simpler sentences: Biden's father had been very well-off earlier in his life, but suffered several business reversals by the time Biden was born. For several years, the family had to live with Biden's maternal grandparents, the Finnegans.