Transcript for Little Boy's Firefighter Wish Granted
It is time for us to do a little update, by the way, on our believe campaign with macy's. Time is running out to get the letters to santa. We're closing in on our goal for the believe campaign. Today, by the way, is a very ial day because it's macy's national believe day. It's an important day. And you can help out a lot today. We'll tell you more about that in a second. What exactly you're helping out with. Abc's abbie boudreau with a story on how the letters really can help. Here's an example. Reporter: For 4-year-old brandon, the sound of these fire alarms and sirens this morning aren't just a surprise. They're a dream come true. This young boy is a living miracle. Since birth, he has not had working kidneys. Instead, he suffered through painful and grueling daily dialysis, just to stay alive. He wanted to be a fireman. Is that a fireman jacket? Reporter: It's been his wish as long as his family can remember. I think it's time to go to work. Let's get dressed. Where is his helmet? Reporter: And today, that wish will become a reality. He's joining the fire department. Why the tears? Because he's been through a lot. You know? And the fact that he's here with us today is awesome. Reporter: Brandon's adventure begins with a fire truck ride. Then, a helicopter tour of the fire district. Have you ever been up in a helicopter before? Yeah. For medical reasons. Reporter: This time, not a medevac taking him to the hospital. Bujoyride, bringing brandon joy and, well, eventually, a nap. But for one special bystander, brandon's uncle, all of this isn't just about granting a wish. It's about saving a life. And you're playing a real special part in all of this, right? I'm the actual donor. And I've decided to come forth with this after seeing what he's been going through. Reporter: He will soon be giving the ultimate gift, one of his kidneys, to his nephew, brandon. But today isn't about hospitals. It's about hope. And a wish come true for the happiest little firefighter ever. For "good morning america," abbie boudreau, abc news, los angeles. And that's the kind of thing these letters can do. Thanks, macy's. By the way, a little drumroll, as we tell you. It's incredible. The total, 744,838 letters. That's awesome. That has translated into dollars that macy is kicking in a dollar for every letter. It's national believe day. They're going to grant 70 wishes across the country today. But also, they're going to double every letter that is stamped and collected in stores today. Macy's is going to give $2 a letter. So, you've got to help today because you're really going to make a lot of extra wishes come true. You go to macy's. You see the big, red mailbox. You do your part. That's fantastic. That is great. And thanks in advance for all of you. For more on the believe campaign, goodmorningamerica.Com on yahoo! Coming up, holiday must-get giveaways for your teens and
This transcript has been automatically generated and may not be 100% accurate.