If you're looking at this page we take it you want to assist someone with mental health problems. From our personal experience what helps are the following; 

Listening to us and showing that you're listening, repeat key parts of what we're saying so we can feel that you understand us. You dont need to have an answer for everything that we're saying, just listening helps. 

If you have questions and you can see we are in distress, make them short answer questions or yes/no questions such as "are you experiencing some negative emotions towards what's been said?" or "do you feel safe enough to continue?" or even "would you like to elaborate on that?" Simple questions are better when we are in distress as we can answer without thinking much about the answer at hand. 

Validate our feelings, you dont need to agree with how we are feeling but you can always say "I can only imagine how tough that is for you" or even "your feelings are yours and they are real" basically what im trying to say is let us feel our big feelings without feeling bad about it.

Dont bring up questions or facts about loved ones, we know you mean well however saying something along the lines of "how would ___ feel if you did this?" Or even "think about ____" this just makes us feel guilty, bad and can be a big trigger for us. 

Respect our feelings and always at the end ask us how we are feeling mentally and don't suggest straight away that hospital is the answer because more often than not, it isnt and we can become dependant on being in hospital if it is suggested too much - hospital is there for extra support when needed, not every crisis needs it though, again, respect our thoughts and feelings, validate our thoughts and feelings, not everything needs a solution - sometimes we aren't even looking for a solution, just someone to talk to and to listen to us.