Realizing that the one you started to like didn't really like you just hurts
This is just my opinion! But I think the last line doesn't necessarily mean Tengoku doesn't like Aoki....I think it's just whenever Tengoku told him "I'm looking at you," aoki thought to himself "ah, I'm being cared for and comforted by someone who sees my pain and suffering, who sees me for who I really am" it's like being reached out and comforted...which he now realizes he is hurt but Tengoku has just been looking at his hurt self which doesn't completely define who he is now. Sure, Aoki's relationship with his mother has a strong impact on him today, but his past self is not his current self so that's what I think the last line meant.
Also...bc Tengoku had done this same looking at you for who you are thing to his brother...means he isn't ready to let go of his past pain...and until he does he probably won't admit to or want to love Aoki in fear of being betrayed...his relationships have all reflected his desire to attain his brothers love. So I guess you are right! Maybe tengoku doesnt understand his own feelings and maybe the feeling isnt mutual...just yet. It is definitely painful ;___;
Finally an update! Waaahhhh The golbins look so cute especially the slimes. That face made though Hiel be lookin scary . Can't wait for the next update