Complex sentence: Meredith moves to the completed dream home and sells her house to Alex Karev, who purchases it as the only true home he's ever known and continues Meredith's tradition of keeping the house open to any "strays" needing a home.
Split into simpler sentences: Meredith moves to the completed dream home and sells her house to Alex, who purchases it as the only true home he's ever known. He continues Meredith's tradition of keeping the house open to any "strays" needing a home.