What about me? Growing up with a seriously sick sibling

Teachers and others who interact with siblings can be very useful, providing ears and eyes in school to be sure that a sibling isn't lost when a child ails. Grief counseling can help, Kevorkian said. Dreams and goals might have to be revised.

One of the best helps is not overstepping, families who've gone through crisis say. Don't, for example, assume that parents have had the same conversations you'd have with your kids. The Flash family has an online page for updates and support. One friend posted, "I know you'll survive this." That was how Sara learned she might die. The family had been focusing on treatment.

"It is scary enough to go through cancer treatment without having to fear dying at age 12. I never, ever lie to my children," said Allison Flash. "But I believe there's a line between a responsible and irresponsible amount of information."

If communication is open, patients and siblings get support. If they can talk about love and fears and what they're going through, Kevorkian says families do OK. "This is the launching pad for how the healthy children end up coping with loss, probably for the rest of their lives."

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