Does anything help? Can another person do anyt…

Does anything help? Can another person do anything to make you feel better? I'm asking genuinely, do you have general tips? I know someone who has crippling depression and I've seen firsthand how damaging it is.

Listening without judgement helps for me. But that’s just me. Someone who will tolerate me in my rawest state (crying, babbling etc.).
For me, talking – even if it is an incoherent mess of words – helps a lot. It just allows me to get things out, you know? Unleashing, if you will. 
i’m not saying this works for everyone but it works for me. When someone talks about “darkness” and “demons” all this other flowery language, try to understand what they’re saying. Don’t criticize them for using silly terms. They’re just trying to make sense of it all. For themselves, not just you.
If they (and I’m talking me here) talk about suicide, don’t think “They’ll never do it”. Don’t assume they are saying what they’re saying for attention. Listen and try to understand. It might not be easy but try. Show them you’re trying if you can. Offer an ear, a shoulder to cry on… Shit, offer a hug. Offer to take them out for a drink. Or food. Offer to smoke them out. Whatever they might enjoy.
Just be there for them. You don’t have to solve their problems. You’re never going to solve someone’s depression. Just be there.