Unimaginable cruelty marked the beginning of Youssif's story.

At 5 years old, he was attacked by masked men as he played outside his Baghdad home in 2007. The men poured gasoline on his face and then set him on fire. His parents wondered, given their child's horrific injuries, whether he would ever smile again.

But Youssif's story struck a chord with CNN's millions of viewers and readers worldwide.

Just months after the attack, the boy and his family came to the United States with a single suitcase. Their living expenses and medical expenses -- hundreds of thousands of dollars -- were paid in full by the kindness of strangers.

The family was granted asylum in the United States and still calls California home. CNN's Dr. Sanjay Gupta has been following Youssif's journey since he arrived in the United States and recently traveled to California to visit Youssif and see his progress.

Gupta says it's hard to believe that this is the same Youssif CNN has been following for nearly six years. The boy has undergone 19 operations and a total of 61 procedures at Grossman Burn Center since 2007.

Now 10, Youssif is very much a typical American fifth-grader. He's smart and confident. His favorite subject is math, and he tells Gupta that he hopes to be a doctor someday so he can help other people.

When asked whether he has any trouble making friends, he's quick to respond, "No, it's easy. Whenever a new person comes, the next day, we're just friends. No one is ever mean to me."

Youssif is now standing tall, thanks to the strength of his parents who risked so much to move to the United States. His father, 30 years old, still fears for the safety of his family in Iraq and prefers to keep his identity concealed as well as the full names of his children.

CNN: How has life been since we last saw you?

Youssif's dad: His life is getting better and better. He's changed a lot, as you know. His English is great, and he is making a lot of of friends. He is much better than before.

CNN: How about you?

Youssif's dad: Life is getting really hard, and I'm just doing my best to keep my family happy and my kids.

CNN: Are you happy here in the United States?

Youssif's dad: I am happy, yes. I am happy especially because I see my kids happy. It means a lot to me. I see them happy. I'm here for their future.

CNN: Do you think you can do it? Can you make a life here in the United States?

Youssif's dad: It's not easy. I have two part-time jobs ... but it's not even covering even the rent. I get a little help for food from the government. I'm trying to find a full-time job. I'm just trying to make it all work.

CNN: Youssif seems happy today. I know you're happy about that. Does he know what the rest of the world is like?

Youssif's dad: I think he's a smart boy. He knows what's going on. Sometimes he comes and asks questions like a big man, not a little boy. So I think he knows what's going on.

CNN: Do you worry about that -- when he goes to a new school he's going to get teased?

Youssif's dad: Yes.

CNN: Does a father prepare his son for that?

Youssif's dad: We have to be strong, and then we have to make him strong, too. I let him know that if anyone is going to come to you and tease you, you have to be smart and think before you do anything wrong.

CNN: Do you worry new wounds will be opened up emotionally?

Youssif's dad: I don't know about the new kids, how they're going to act towards him. He'll be fine with the friends he has now, but with the new kids, I think it is going to be hard.