You're doing a good thing by supporting her, especially since you have personal experience. Try these resources:
www.teenhelp.orgYour Life Your Voice
www.yourlifeyourvoice.org/AskIt/Pages/default.aspx1-800-448-3000
www.youthcrisisline.org/As for the suicide ideation, this sounds tough, like she feels hopeless. You can certainly practice your validation skills that you know here. You may want to pass this onto your son, as well as looking at the SI info in the red Emergency button at the bottom of every thread. "You have so much to live for... ." or the like is invalidating, right? If you know this, you can coach your son and others in her life.
I remember feeling like this as a teen and having no one to talk to, or I felt safe with to tell them how I really felt. Good that she has you