You may think he's having a mental or nervous breakdown, but he's not. His behavior will be very much out of character and will cause you to question whether he has a brain tumor or is suffering a breakdown...but what he is experiencing is an emotional crisis. Emotions for them run very high during this time of crisis and it's not about the red sports car or the young chick on the arm...but truly their emotions and facing childhood issues.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.