Acknowledge the Anguish and Pain. Be Present...
"I don't know what to say to someone in pain -> like I don't know how to make them feel better..."
This is a common misconception. We believe in something different -> let someone feel sad. We aren't supposed to fix anyone, just be there when they are hurting. Let a person talk your ear off - or eyes crumble out of your head from reading so much.
Say things like, "What else is there?", "I actually completely understand where you're coming from. It doesn't feel good. But the pain always passes for me after I do 'X' to cope.", and there are so many more things you could say. Stay with the person. Don't make empty promises. Be there for them, that's all.
I don't think we understand fully the power we ALL have to help one another by being present.
The idea of giving an ear or your eyes for hours could literally prevent a 15 minute eulogy. It is not audacious of you to think you can do this.
Always encourage someone to get professional help, of course. But there is a major problem in the mental health field, there are not enough professionals. There are too many hours needed. That's why wellness programs and non-profits exist. We, meaning all people in Project Refit, aid the mental health professional by just giving an ear/eyes to one another.
Peer-to-peer support can be a major game changer in the battle against suicide - especially for those in rural areas.