Trump is clearly a dangerous narcissist. I have no doubt about this whatever. If Trump at any point needs to choose between suffering damage to his ego or blowing up the planet it is not at all clear he could stop himself from blowing up the planet. Ego is so all consuming for narcissists that they will do absolutely anything to avoid loss of face.
But won't people around him stop him? Unfortunatley the system doesn't work like that. I heard a general explain that the exact protocol around nuclear decision making is classified, but the public should be in no doubt the system is designed for speed to carry out presidential orders, it is not designed for deliberation or debate.
Americans should have thought about this and voted accordingly. I don't know what can be done now other than cross our fingers and hope for the best. I am not optimistic about survival of the next few years if Trump is in charge. I guess the best hope is that he is arrested or impeached fairly quickly.