Starting the conversation when a colleague seems low

Most people worry about saying the wrong thing, so they say nothing. A simple question in a quiet moment is usually enough to start (sample note).
Ask twice: ‘How are you doing, really?’ Then listen more than you speak, and do not try to fix everything in one conversation.
If someone is in danger, call 911. Otherwise, help them find the support your workplace offers, and check in again a few days later.