The best thing you can do to help is to keep an eye out hear and reach out when someone is hurting. That's the biggest contribution possible. There's also /t/psychology and /t/suicide for general discussion of psychology both clinical and research and suicide specifically where I'm sure you could share a lot of that technical expertise to an interested audience.

Honestly, being a mod doesn't put you in a special position to help, it just means that I have the responsibility of making sure to keep out the judgement and recrimination.