The man is quite obviously mentally ill. Amendment 25 was written for exactly this sort of problem.
https://www.cnn.com/videos/politics/2019/02/15/trump-border-wall-rose-garden-tirade-sued-sot-vpx.cnn/video/playlists/this-week-in-politics/
https://www.cnn.com/videos/politics/2019/02/15/trump-border-wall-rose-garden-tirade-sued-sot-vpx.cnn/video/playlists/this-week-in-politics/