Might I suggest a slight tweak of the last sentence, "With what kind of eyes were they looking at me..." "...I couldn't notice that." Together this line sounds very stilted and unnatural. I'm not 100% sure what Tatsuya is trying to say, but my best assessment is that he's saying something like, "From the looks they were giving me... I didn't notice something."
Does anyone know if that's the general meaning of his words? Either way, can someone check these two lines to see if this translation can be smoother?
I didn't really noticeThis time, this beautiful white being, and----this stunning lady in black.I'm glad that I'm finally able to meet the people who know about my big brother's existence...with what eyes they looked at me.