Just recently, she had moved out of the family home to live independently in an apartment. Her father said she was ready to make her own decisions, take care of her own finances.

She had also been practicing on Saturdays with a Special Olympics basketball team, which was scheduled to play a tournament in Fremont two days after their return from London.

On the flight home, her father said she was full of anticipation about playing.

But during one of the games, she was struck in the head by a basketball. She complained of a headache afterward, though she frequently suffered from migraines.

The father said he took her three times to emergency rooms for migraine shots over the weekend. On March 2, he took her to her regular doctor. Her vital signs were normal. The doctor said it was probably just a cold.

Then, on Thursday, after her headaches persisted, the father took her to the emergency room at Methodist Women’s Hospital, just off 190th Street and West Dodge Road. It was the first time she showed low oxygen levels, a sign of breathing difficulties.

“The testing began and it all hit the fan,” her father said. “My initial reaction was, ‘Oh my God. What next?’ ”