Not OP but here you go. I work with young people and have had suicide prevention training multiple times, this is a recurring mantra that not asking about it is much worse than asking.

Not the original commenter, but I know it's included in the yearly training for Army civilians and soldiers. We have to take suicide prevention training every year. I don't think the training itself sources the info though. Also I don't know if you can access the training without a CAC. In any case, they say that it is just a myth. You don't have to tiptoe around the idea of suicide. It's better to ask someone if they're thinking about it if you're truly worried that they are.