For now just try to keep things calm
for him. Warm baths, instrumental music
for relaxation. Anything that makes him comfortable, just ask him.:O)
2 overseas trips in 6 weeks is alot! let him ease back into his own routine for next couple of days and see how he does. If things are not better call your family doctor, to get his opinion.
Keep him of coffee as best you can. Also, having his comfy things he likes near may help. Keep anything that is stressful to him away for couple of days.