I believe most of those who have advised him are concerned about life and limb. When an American President speaks things happen. Consider this:
1. Serbian Nationalists buoyed by reports of a Pro-Putin White House are keen to reverse the Kosovo reality. The Ultra nationalist PM sent a train in to Kosovo to provoke war. He already counts on Russian support and now believes the US would not budge.
2. There are reports of the Bosnian settlement coming apart because Trump is seen as anti-Muslim and thus removes the only support Bosnian Muslims had;
3. The fact that he has a Slovenian wife who may harbour similar prejudices as Slovenians towards Muslims is cause for concern
Now add this to a loose tongue and see what happens. People can easily die.