AS AND AS: PLS DON'T DO IT.

My neighbour's child just died this morning. He was 12 and he's been in the hospital since last week Monday. My neighbour had 3 kids. The first one died in 1999 at 13years old, the second one died in 2004 at age 9 and this one just joined his sibblings. All his children are dead. What killed them? My neighbour is As and married a woman with AS. Sad right?