I believe that Nick khun should come back. The fault was not all his, although the blame has been placed there. He drank with the company, couldn't somebody take over? It was a mistake from all parts. It is time to reflect, learn and come back a better person. By this time Nick khun must know who is a true friend and who is not. It must be very sad and lonely to realize this.
Come back and go on stronger. Let go of everything that is damaging to your person. Use this time to clear up your body and mind of negativity. Do good not only for others but for yourself.