I'm Not Crazy

Twins, a brother and sister. The boy was named Dekatreea and the girl was named Maylea. Maylea was the motherly figure to her slightly younger twin, since their parents hardly spent any time with the twins. She thought maybe they were afraid of them. Dekatreea secretly hated his parents for giving him what sounded like a girl's name, "a weird girl's name" he thought. He knew the name was Greek, but he didn't know what it meant.
One day, Maylea was screaming horribly and wouldn't say why. Dekatreea tried to help her calm down by sitting her on their old reading chair and whispering calming things in her ear. Their parents couldn't take anymore of it, so they took her to the hospital. The doctor's ran multiple tests as Maylea continued to scream. They found nothing wrong, so the next step was psychiatric therapy. Maylea wouldn't talk to the therapist, so this helped none. The next early morning, Maylea's heart stopped and the doctors announced her dead. Nothing unusual was found during the autopsy. The doctor's told the family Maylea died of unknown causes, that her death might have been related to psychological traumatic reasons. Dekatreea wouldn't have any of this, and now his theory lives on inside his head a year later.

~~Written for This phobia contest.