Transcript for 6-year-old battling leukemia becomes UPS driver for the day
Finally tonight, a mother's day wish come true. Reporter: Tonight, just in time for mother's day, a mother's wish for her son is coming true. 6-year-old Mateo Toscano from Stockton, California, has been battling leukemia for years. Because of his medical condition and the pandemic, Mateo stays indoors. But he always loves watching for the ups delivery drivers. So when the nonprofit make-a-wish foundation told Mateo they would grant him one wish, we knew just what it would be. Hi, David. Every day my mailman comes and delivers like mail and I just, like, think I want to be just a delivery man. Reporter: He's ready. I would like to deliver packages to the mail and drive my little ups truck. My very, very own. Reporter: And so Mateo partnering up with ups driver Dave cundari. You ready to see your new truck? Reporter: Opening his truck. Unloading Mateo's own U.P.S. The driving test. He passes. Good job Mateo. Reporter: Loading up deliveries for Mateo's mother and grandmother at Macy's. Hello David. Reporter: Dave, on the job 37 years. Working through this pandemic. Being an essential worker Reporter: The most important delivery for mismom and grandmother. His mom. He had his wish granted today and it was an amazing day. Mateo telling us what his mother means to him. She means, like, love to me. Happy mother's day. I'll see you at 9:00 P.M. Eastern for our special "20/20." Good night.
This transcript has been automatically generated and may not be 100% accurate.