Some call it cognitive therapy.
The parents of these high school students would be wise to take time from work for family/medical leave or personal time off; and simply spend time with them. They should not be left alone as if everything is okay and life simply needs to go on. These young people are suffering from PTSD, it needs to be diagnosed and understood by the parents and the students as well. This is not a minor issue.
Basically, don't let them out of your sight until a therapist is convinced they are over the worst. Such disorders make behavior unpredictable, but, medical and psychological supervision and time will heal the pain that is too present to ignore.
Two suicides in two days is not a minor social issue. This is a profoundly disturbed group of young people and it isn't going away without sincere efforts by parents to secure their children into this world. The healing from these tragedies are not simple and they impact lives with incredible realities. The one student was in college already and could not attend classes because she was having attacks of fear of being killed. It emotionally paralyzed her.
The scars for these young people run deep and don't show until it is too late. They need to talk to their parents and they need to understand they can deal with their pain over time with the wisdom of how to recognize their own mental illness and have the ability to mobilize parents when they are feeling desperate. The parent and child relationship has to include talking honestly about feelings and running emotionally to the parent when feelings of dread or self-harm erupt.
This is tough. Sometimes no matter how hard parents try, it doesn't work either. But. love is important and an idea of a safe haven away from harmful thoughts is important.
They are worth the trying.