One heart in two souls

Context

Simon told Louis to leave London. Without giving any reason, Louis texted Harry telling him he was leaving London in two hours. Harry run after Louis trying to catch him before he arrived at the airport. Harry run without looking the traffic and just when he was about to cross the street and entering into the airport, a car hit him, leaving him in a very serious condition.
Louis spent nights right beside Harry's bed, but the doctors didn't had any hope for him to wake up.
After being in coma for two long weeks, he woke up, but his heart didn't work as good as it did before. He wouldn't live more than two more weeks. The only way was a heart transplant, but the donor list was too long, at least it appeared a last minute donor, Harry will not survive, so Louis knew what to do.