It might seems toxic but i don't think it is? He didn't really harm him or anyone close to him, that girl was already infected in the first place. The light haired boy was attached to the past and unable to let go, so all he wanted to do was die when all the people he loves left him. I don't like him a bit because he didn't hesitate or try to stop the infection and was ready to leave his "friend" that helped him with almost everything.
Uruwashiki Shuen