How distressing for your brother. The central issue according to your description is to identify the trigger(s) for your brother's episodes. Generally, such triggers are related to deep-seated fears and/or mental disorders that can range from mild to severe. Since his psychiatrists have not identified the trigger or reason for these episodes, my first suggestion is that he see a qualified psychologist for complete psychological testing. The testing will reveal clues about his personality, coping mechanisms, fears, and functionality. An interview alone is not able to identify the extent of these areas. Another suggestion is that he consult his psychiatrist about the possiblility of an anti-psychotic medication and an anxiolytic for use while abroad. He would benefit from keeping a daily journal, as well, both while at home and abroad. While abroad, he should record his perceptions and feelings at least twice daily; this could be invaluable in the diagnostic process. I hope this is helpful to both you and your brother.
Good luck to you both,
Faye, RN, MSW