Biden didn’t actually intentionally pardon him, Biden signed off on a broad commutation/pardon for many nonviolent crimes who have had good behavior.

President Biden is commuting the sentences of nearly 1,500 people who were released from prison and placed on home confinement during the coronavirus pandemic and is pardoning 39 Americans convicted of nonviolent crimes. It’s the largest single-day act of clemency in modern history.

This particular judge just happened to qualify by chance. Some kids in similar situations might have also been eligible for the same type of pardon.