Charles Ellicott Commentary 2 Kings 13:11

"And he did that which was evil in the sight of Jehovah; he departed not from all the sins of Jeroboam the son of Nebat, wherewith he made Israel to sin; but he walked therein." — 2 Kings 13:11 (ASV)

But he walked therein. —Hebrew, in it he walked. The pronoun is collective in function.