
No. Touma isn't gay.
All we know is that Touma use to be extremely active, rebellious and selfish and now is really subdued and polite. He is insistent that he is not allowed to be selfish, even though Kinako and Akito are aware and welcoming of their emotional needs.
A large part of that is grief and ptsd, but I am also wondering given the authors other works, if there will be a thread of coming out. This manga deals with different, un-idealized family dynamics like divorce, single parenthood, neglectful parents, unrelated guardians. We've seen Chizu's parents, but I wonder if there will be more development of trying to successfully parent a gay child.
I love how Kina is so blunt about child-rearing. I am glad that while she scolded Rina's mom, she also gave some grace.
Given the author, I wonder if Touma is feeling particularly on edge and that he can't be selfish because he is gay.