It's this new thing I'm doing! I'll a riddle on a specific day, and you my dear will comment the answer!

Now, what's the answer to this riddle?

A young man looks at a photo with 2 people in it. "Brothers and sisters I have none, but that man's father is my father's son."

Who was he talking about?

Post the answer in the comments below! If you get the right answer, i'll give you a free sketch of any character you like! No OCs tho.