If he's staying in a western chain hotel, there will be OJ available at breakfast, through room service and (small bottles of a western brand) in the minibar, although it will be expensive. If he buys a big container at a 7-11 or similar, he can pour it into empty plastic water bottles to fit into a small refrigerator or minibar (but hide it when the room is being serviced). IIRC some of the OJ in small plastic bottles is processed in a way that the unopened bottles don't require refrigeration but check on this.

BTW, will he arrange for a refrigerator in his room for insulin and other medications?