Hello, My Boyfriend Recently Took A Laxative. We're Currently Holidaying

Hello, my boyfriend recently took a laxative. We're currently holidaying in Bali and he hasn't been consuming much fibre in his diet. He has now had severe diarrhea for over two days. It's currently 3.30am and he's up again, he also has bad stomach pains - so much so that he constantly feels like he's going to throw up. He's been drinking lots of water but it just seems to be running right through him.. What can I do to help him??