Zenos' mother died, we learned it from The Hunt Begins.
"From the beginning, Zenos was alone. His lady mother succumbed to illness shortly after bringing him into the world, and his lord father was seldom present, occupied as he was with his military campaigns and political maneuvering." Link:
https://www.reddit.com/r/ffxiv/comme...s_the_offical/
Anyway, I do not find EW disappointing, I like it more than ShB! I was happy every time Zenos showed up, too bad he didn't have more screentime. That final fight was amazing and I wish I could replay it. A part of me wants him back but an other part thinks he got a satisfying ending.
Other people find Zenos boring but I find his whole being heartbreaking. A force of nature whose only happiness is fighting me because he doesn't know better. He grew up alone, neglected, no one loved him, he was trained to serve the Empire. I admire him for coming back from death and obsessively pursuing that one happy moment just to die again. I think it's beautiful in a sad, twisted way!
I'm not sure if "redemption" would work for Zenos. He doesn't want to become a better person, he just wants to feel that moment of happiness again. I'm glad he decided to help me to get what he wanted and I made him happy in his final moments. But I also wish I could show him that there are many temporary happy moments in life (besides fighting). I wish I could heal his damaged soul. I wish I could go back in time, steal baby Zenos from Varis and raise him with a lot of love.

Good night, sweet prince!