Xiehou Ta de Shaonu Shidai

"Mom, I'm sorry. Please don't die." When Henry realizes death is at his mother's doorstep, he strikes a deal with a lifespan dealer to give years of his own life to his ailing mother. Now, his mother is a 20-year-old college student with a full life ahead of her, and Henry devotes his remaining days to helping her live life to the fullest. But things turn complicated when his friend falls in love with her!

(Source: LINE Webtoon)