He sought Ahaziah - See a different account 2 Kings 9:27; (note), and the note there, where the accounts are reconciled.
Compare the marginal reference. Ahaziah after remaining a while at Megiddo, removed to Samaria, where his wounds could be better cared for and concealment might be easier; Jehu‘s emissaries discovered him there; they took him to Jehu, who happened at the time to be at Megiddo; and then and there Jehu put him to death. The narrative here is therefore supplementary to that of 2Kings, and finds its proper place between the clause,” He fled to Megiddo,” and the words “and died there.”
And when they had slain him, they buried him - Jehu‘s emissaries killed him but allowed his servants to bury him (see 2 Kings 9:28).
No power - As Ahaziah was but twenty-three at his death (2 Chronicles 22:2 note), he had no grown-up son to take the crown.