Read this excellent article from the Harvard Business Review entitled, How to disagree with someone more powerful than you.
Life is brief.
Make a difference. You’d better make it now, as your life may be gone any minute.
If you don’t speak up (appropriately & effectively) to stop the train wreck, the train may indeed wreck.
Ego (that whispers in your ear to be afraid) is the enemy. Face it with real courage and do what needs doing.