Who is that green haired boy?

During the Sport's Festival Fuyumi watched an unknown boy breaking his body with his own godly strength give up his chance at victory against her brother. All to save her brother's spirit. To bring him back from the darkness he was surrounded in. However she once met that same boy years ago. His mother was her Mother's nurse at the hospital and that boy would often help. That boy all those years ago helped her and her mother see the light past the Todoroki curse. What happens if she visits her mother and he is there with her brother?