I'm not a lawyer either and I'm sure you are right the rules vary greatly by jurisdiction. But it is clear to me the family has legal standing to successfully sue for wrongful death. They did not sign a liability waiver and no one can sign away their legal rights for them. They experienced a personal loss so they have grounds to recover on that.
This is a very sad story. Because of that a jury will likely award a lot of money, right or wrong. I personally think there's too much money being awarded in civil trials and too many lawyers profiting too much off the misfortune of others.
In Jamaica they have a public tourist attraction where people climb rocks up a waterfall. This would never happen in America for liability reasons. The park has a permanent first aid station and ambulance on standby. I'm sure if you get hurt you're not getting much if any money from anybody. The vast majority of people do not get hurt and have a lot of fun. Should the waterfall be closed to all because some will certainly get hurt? The lawyer-free parts of the world are very different than America. Generally you only find trial lawyers where there are a lot of riches to confiscate.
If you were to fall on the rocks in Jamaica they might give you a pound of Blue Mountain coffee and a Bob Marley cd .. now THAT's valuable ;)