Unfortunately at this time of night there wont be a pharmacy opened anywhere
In the morning, have him go to a pharmacy and ask for something for a koev beten.
And no, pepto does not exist here.
I know there are a few pharmacys open around israel until late. I know there's one in tel aviv for sure. Not sure exact location sorry.
And if he wants something like pepto bismol maybe gaviscon will help him they have that in israel.
Also maybe optalgin might help (think they come in drops and pills as well)
I don't actually live in Israel but I've been thru the same troubles whilst there! Hope he feels good!
I am pretty sure the pharmacy in Center 1 is open till 12. The new part of Center 1, Called superpharm I think, near tachana merkazit.
I think the one in ramot mall open as well until then.
Tell him to drink hot water, if can get chamomile tea even better...maybe he can get a hot water bottle to put on his stomach...
He should take little sips of water so that he shouldn't get dehytdrated.
Just so you know, pepto bismal can make certain types of food poisoning / stomach bugs worse. I recommend he wait - most of thigns disappear within 24 hours. And if it doesn't, then he should see a doctor.
A little off topic but in response to the other comments here, fyi each (major) city has an on-duty pharmacy so there's always a pharmacy, somewhere, open. The Jerusalem schedule can be found on the municipalities website.