Complex sentence: The current head of the comital family, Count Cesare Filippo Ambrogio Sesto (b.1954) lives in Tuscany; his heirs are his brother Count Vittorio Giulio Spinola Sesto and heirs thereof.
Split into simpler sentences: The current head of the comital family, Count Cesare Filippo Ambrogio Sesto (b.1954) lives in Tuscany. The heir is his brother Count Vittorio Giulio Spinola Sesto and heirs thereof.