Grandson had an accident (Diarrhea)

We're currently in Mexico staying at a timeshare. My daughter sent her son down here (Jr. High School) with us during his summer vacation.

He's been here almost 2 weeks now and has been having a great time. Up until now, no health problems at all.

But this afternoon he started getting some stomach cramps/pain when we were at the beach. I was walking him home since he felt like he had to use the bathroom but was unable to control it and ended up having an accident. Luckily we were already in the building at the time so nobody saw and it was relatively easy to get cleaned up.

We've given him some toast, along with gatorade to replenish his fluids. Also gave him some Pepto and it seems to have slown the
diarrhea down a bit.

We're supposed to go on a night-time jungle trip in a jeep this evening and made the booking nearly 2 weeks ago since it's hard to get a spot. One thing is that it's a drive-tour, meaning we (Myself, husband, grandson) get a jeep to ourselves and basically follow behind the tour operator so we do have some degree of privacy.

My question is - do you think it would be alright to bring him or should we cancel? He says he feels alright for the most part and really
wants to go. On the other hand, there obviously won't be toilets out there and the trip is about 2.5 - 3 hours long. I'm not sure what we'd do if he has to use the bathroom. Anything we should consider taking with us in the jeep if we do go?