As he was now going down (ēdē autou katabainontos). Genitive absolute inspite of the fact that autōi (associative instrumental case with hupēntēsan aorist active indicative of hupantaō) is near.
That his son lived (hoti ho pais autou zēi). Present active indicative preserved in indirect discourse (cf. the words of Jesus in Joh 4:50). Note pais here (only example in John), huios in Joh 4:50, paidion (diminutive of tenderness) in Joh 4:49.