His parents died in 1886 and 1887, when he was a boy.
At the time your parents died, we were only kids.
Both his parents had died when he was only 15.
His parents had both died by the time he was 10 years old.
When my parents died, he became a father and mother to me.
Both his parents died when he was still a child.
Both his parents died when he was 12 or 13 years old.
I was an only child, and my parents died young.
His parents died in a fire when he was very young.
His parents had died before he was even a few weeks old.