I'm curious if there has ever been any explanation from the family why they chose that location for camping? I'm not trying to imply anything negative, just wondering why they would drive 120 miles to such a rustic and remote campsite? Perhaps I'm posh, but my family and I prefer state parks where we can enjoy washrooms, a playground, and Junior Ranger programs. The remote campsite seems like an odd choice to me to bring a 2 year old and an elderly man (who may be somewhat physically and or mentally limited). I could understand if it were just a couple of young men on a hunting trip, but a family? Were they just stopped there overnight as they were travelling elsewhere? Did they plan to hunt in the area? Do they have ties to the area?
It really is not odd at all. If it were, idaho wouldn't have dispersed/primitive camping. I would guess that many people in that area are like my family - when we go camping we want privacy. We have camped in areas just like that (even without water) with very young kids. We camp with kids as young as 4 months old.
This campsite really isn't very remote. Yes, it is off the beaten path but not remoye. They could get water at the nearby campsite if they ran out.
On our recent trip we drove 7 hours (and family from Utah drove further than that) to salmon,id to camp. Once in salmon it took us 90 min to drive 25 miles to the campsite (on all dirt roads). We hoped to camp in a certain light use campground with water, but were willing to go to plan b and do dispersed camping with or without water and even without designated fire pits and toilets. We had 11 people camping with us. We just wanted to get away from civilization.