Let's be honest here, he knows what he's doing, he always has. Even if he acts stupid, you gotta give him way more credit than you are. He literally controlled the entire election and voters like puppets, stirring up and invoking stupid retaliations from SJWs to get non-SJWs annoyed at liberals and all riled up so they would go vote for him out of frustration. Or you forgot that?
A large chunk of the people that voted for him were literally voting just out of annoyance from SJWs! He didn't get to be that rich by being dumb people, he's much smarter than you think, if you can't even tell he's putting up a dumb guy front, perhaps you are the idiots
Even if WW3 happens, it will be over in an instant and no matter what, there are actual war treaties you can't just ignore, preventing direct conflict between superpowers, but indirect on a third country's soil is acceptable, reason any and all war takes place in the middle east, so no need to really worry. Add that countries nowadays have to upkeep a public image, as the UN isn't just USA, so the other countries can easily intervene and USA loses all it's power then, it will just be like pre-WW1 Germany, lots of military might but no one supports them.