Complex sentence: After her death, he relocated to Japan to honour his wife's wish to care for her parents, since she was an only child, and her parents were both in poor health, in their 70s, and lived on a small pension.
Split into simpler sentences: After her death, Wong relocated to Japan to honour his wife's wish to care for her parents; she was an only child. Her parents were both in poor health, in their 70s, and lived on a small pension.