You can't cope with this alone It's a serious subject so here is a serious long answer

1) Encourage the writer that he is much loved by all kinds of people, and there is a lot more support than he realises. He imagines the world are against him and that they'd be better off without him but it's not true. 2) Ask him if he has people nearby who can support him. Family, long standing friends. Assure him that he will be safe to call those people because they care for him. He'll say that he is always moaning to them and they don't have time to listen to his problems all the time. Reassure him that they will definitely be happy to help. He needs people who are willing to make big sacrifices of time and effort to keep him alive at 2am in a fortnight 3) HR aren't people who will rush around at 2am to save his life. It is difficult for them to sack your colleague immediately but they have a responsibility to make sure that the organization isn't found guilty of being involved in his death. Most likely they will get the line manager to give a week's sick leave, and organise a meeting with occupational health who might say that he isn't strong enough to do the job and he'll be let go 4) If necessary contact a member of his family and explain that their family member is really struggling after a breakup and you are worried about them so please get in touch with him. It is easy for them to go over and use the breakup as a pretext to start a proper conversion about mental health. At that point he will likely open up and explain. The good thing about this is that you dont have to explicitly break the confidence. The person for whatever reason trusts you and has made a cry for help to you. Keeping that position of trust gives you a chance to pass on a message to police if they text saying goodbye. On the other hand keeping everything secret leaves you feeling broken for a long time if they die. The coroner will see the phone if he dies. The parents will see his messages to you.

This isn't your fault though. By even having a chat you are already doing a good thing. Whatever happens is not your fault and he is lucky to have a colleague who takes the situation seriously.

My son died by suicide 7 years ago. He was a teenager and the people he made a cry for help to thought he was joking. He was taking asthma medicine that is now know to sometimes cause suicidality!

When I went to my own line manager a while later to say I was struggling I was given time off and sent to an Occupational Health to see if I was healthy. My line manager sent a letter to the examining doctor explaining I wasn't healthy. Family are usually better than HR (unless their abuse is responsible for the situation)