Take a look at the trauma support leaflet created by the Central Suicide Prevention Team.
It includes nine methods for helping a colleague in emotional distress. The leaflet aims to promote alternative support options to you and your colleagues, especially when you may not want to speak with your Line Manager or HR.
The trauma support leaflet seeks to provide basic, easy to follow and sensible advice on what to do if you are feeling emotionally vulnerable after a traumatic event. Feeling vulnerable is natural as is asking others to support you in a time of need.