I'm not a lawyer, though while a graduate student I completed two courses in the university's law school, Torts and Civil Procedure. I'll always remember the first day of Torts. The arrogant professor began his first class by quoting from a poem which mentioned the term "fellow servant". He said something like "I don't suppose anyone here (about 70 first year law students and me) can tell me what this is from. The poem was related to my field, so I was very familiar with that Butch Weldy epitaph from Edgar Lee Master's Spoon River Anthology, and I quickly provided that information to the professor, who was visibly upset. "never before in 22 years of teaching,(etc)" I ruined his first lecture, which had always focused on the narrow and limited education of most law students.
What an ego.
Cowboyneal, it seems to me that WRONGFUL DEATH is the basis of a potential claim, the tort. NEGLIGENCE is why an event may be actionable, if damages resulted . Also, one does not become an heir until one inherits, something that cannot happen until the person bequeathing is dead. Until then, there are presumptive heirs, persons who will inherit, but who have not yet done so, and who may have no claim on the property. There are exceptions, as with EVERYTHING in the law.
And it is true that no waiver you sign can waive another person's right to sue, except in situations when it can. (See, I did learn something in my two law school classes.)