he died. Not fell asleep! No details of his death, here, in Chronicles, which is concerned only with Judah. Details given in Kings (1 Kings 22:35-38).
Related Commentaries of 2 Chronicles 18:34
2 Chronicles 18:34
34 And the battle increased that day: howbeit the king of Israel stayed himself up in his chariot against the Syrians until the even: and about the time of the sun going down he died.