I think you just have to trust the parents' judgment to know what their children can handle, and when.

There are no right answers here, only people who love each other who are trying to do their best to decide what people can handle.

I learned of my maternal grandfather's suicide by accident, when another relative let it slip over dinner. I think I was in my late 20s when I learned this. Up until that time I believed he had died of a stroke. There had always been conflicting stories about his passing, I had just chalked it up to people's memories being faulty with time.

I was told I must never, ever, EVER discuss this with my mother. To this day I am not certain whether it is because the family has kept the facts from her ("to spare her feelings") or if it is because it was simply a very painful time that should not be dredged up. But so far I have honored this. I can't promise that the day won't come when we won't talk about it. Heck, maybe she'll be the one to bring it up.

I will say from my perspective that I feel that this is important for me to know from a family medical history standpoint. It's been a while since I've read up on it, but I seem to remember that we can be genetically predisposed towards, say, reacting to stress by displaying depressive symptoms. Maybe I'm not getting that quite right, I don't know. But it is part of the medical history, and it would have been helpful to know about this, particularly during my turbulent teenage years.

Teenagers can be remarkably resilient, and mature. I think sometimes these days they don't get enough credit for their ability to grasp complexity. But for now I think you should trust the judgment of the parents. They are in pain too, and just trying to feel their way through it and do the right thing.

Are there support groups/organizations for the families of suicides in your sister's community? (and in your case, in Calgary?) I think this is one area where professional grief counselors can really help.