As he was now going down (ηδη αυτου καταβαινοντος). Genitive absolute in-spite of the fact that αυτω (associative instrumental case with υπηντησαν aorist active indicative of υπανταω) is near.

That his son lived (οτ ο παις αυτου ζη). Present active indicative preserved in indirect discourse (cf. the words of Jesus in verse John 4:50). Note παις here (only example in John), υιος in John 4:50, παιδιον (diminutive of tenderness) in John 4:49.