Typically the counseling is done by the individual having knowledge of what took place. There are times when a Leader might conduct a counseling when that Leader was not present at the event.
Let’s say there was a fight between two Soldiers. A leader could counsel the Soldier for fighting based on the information available, even thou the Leader was not present when the fight too place.
When Should Counseling be conducted?
FM 6.22 Appendix B (soon to be ATP 6.22.1) states that the counseling should take place as close to the event as possible. There is no specific time limit.