Hi there! did you go through the most recent quest? Its the one involving water (don't want to spoil anything just in case haha)
hm I had thought before that since he's a story desire completing his quest would guarantee you getting him, but i'm not completely sure about that... Why dont you try asking on the games discord! A lot of people are active there so you'll be able to get responses immediately which should really help! Heres the invite link: https://discord.gg/GSJkxEV