I Became The Servant Of The Sickly Crown Prince

An 18 year old student who almost got his college degree but died due to a car crash accident. On the verge of his death, suddenly a bright light flashed before him. As he woke up, he became the terminally ill son of the baron who was an extra character in a romance novel that he once read, after chapters later died because of his uncurable condition, how will he survive and surpass his fate?