You don’t say how old the child was, but i would imagine he went through emotional trauma. I would certainly consider him a survivor.
My grandmother was one of the lucky ones. She was a German Jew who escaped shortly before the Holocaust to America, and managed to work and get the rest of her family out a few weeks before the borders were sealed. She came here by herself. As an adult, she was a fiercely independent, but very mean and judgmental person who if you were not on her favorites list, was very difficult to get along with. When I said “I love you” she would sometimes respond, but she would never initiate it except for one time in the final year of her life, when I was on the phone with her and she thought I was someone else.
It was only after she passed away a couple of years ago at 101 that I realized that her entire personality and issues I’ve mentioned were likely from the trauma she had to endure as a child to come over to a new country by herself and be responsible for saving the lives of her parents while she still could. While her life was never in danger in America, I would certainly even consider her, in many ways, a victim of Hitler, and a “survivor.”