If the whole point of the trial testing willpower is to show them painful hallucinations, why did he see a hallucination that didn't affect him at all? It's obviously not the most painful thing for him if he can just shurg it off. Hell, we've seen him get more worked up over his mother and sisters, so we know he isn't just unfazed by everything. So, why did the hallucination show his father of all people? Show his fear of Ode Seeker corrupting his little sister or better yet, show a hallucination of her willingly walking into Ode Seeker's embrace, that'd hurt more than showing his father who he's already apathetic towards.
Oh wait, token sex scene. Gotcha.