Kevin McGuire's older sister, Victoria who started a Facebook group posted a message saying Kevin was taken to the hospital Friday night, CNN reported Saturday.
"Please continue to pray for Kevin and his health, because that is the most important thing. As for Taylor, she is just as depressed as all of us to miss out on this date, and we are so thankful for the opportunity she has given us," Victoria posted.
"Please keep him in your thoughts," Taylor Swift tweeted. "I'll make it up to you, Kevin!"
McGuire, 18, was diagnosed with leukemia in 2007 when he was 13. He lost his hair to treatment before the cancer relapsed. When Kevin worried about getting a date to his prom Victoria started a "Taylor Swift take Kevin McGuire to prom" Facebook page which went viral securing Swift's attention, CNN said.
Swift apologized she couldn't accompany McGuire to his prom but asked him to be her date to the ACM Awards show.