Terrible Dream Leading To Death - Puzzle

Two brothers were watching a horror film on video late one night. One brother dozed off and dreamed that he was being chased by the crazy man from the movie, who was trying to kill him. In the dream, he hid in a cupboard. There was no sound except his heart pounding, and he had no idea where his crazed captor was. He was terrified! At that moment, the video finished, and his brother put his hand on the shoulder of his sleeping sibling to wake him. The shock at that tense moment was enough that the sleeping brother suffered a massive heart attack and died instantly. True or false?

Know here reality! 

Source 

Script Writer of Terrible Dream Story!

What was the incident? 

Just a little lateral thinking required to crack that puzzle.

If that brother was died immediately after his brother put hand on his shoulder then how who wrote about his dream in detail? Hence the incident of death due to massive heart attack is totally fake one! Only possible way to know anybody about died brother's dream is the died brother himself coming in his dream & tell the entire story of what happened on that night.