Saying, "Don't worry, it will all be okay" to someone who is intelligent, informed, and at risk is not comforting.
It's actually offensive and alienating.
If you wan to keep your relationships intact, and if you want to be a comfort to your friends, learn to sit with their concerns and distress without reflexively smothering them in toxic positivity.
It's a habit worth cultivating. We're all going to need it.