Who Was Manasseh's Father? 2 Kings 21:1–18
Manasseh's father was Hezekiah, the king whose reforms Manasseh later tore down. The passage answers the family question quickly, then spends its energy on the reversal and the judgment it provoked.
Hezekiah's Son: What 2 Kings 18:1–8 Says
The passage before us never names Hezekiah's son. It introduces Hezekiah himself and weighs his reign, which is exactly why the later identification of Manasseh lands with such force.
Hezekiah's Prayer and the Added Fifteen Years
Hezekiah's prayer in 2 Kings 20 is not polished, and God's answer is not owed. The passage shows a free, gracious response to an urgent plea, confirmed by a sign rather than guaranteed to every sick person who prays.