Basketball injuries resulting in death are very common.
She must have been hit in the chest at the exact wrong nanosecond.
I had a niece that nearly died from peritonitis from a perforated ileum caused by a gut punch or kick by an abusive boyfriend. She hid the injury for months, until she passed out. Ended up with an ostemy bag for over year before she was healed up enough to reconnect her plumbing.
Maybe somebody beat this kid.