@HighlandLawyer @Di4na @cstross "Filial responsibility" laws already do that.
https://en.wikipedia.org/wiki/Filial_responsibility_laws
The hospital performs "heroic measures" in the parents' last hour of life (out of network of course) and saddles the estranged child with a $15 million dollar medical bill payable to United Health. Neither the parent nor the child ever have to consent to this.
The billionaires haven't just already locked up all the boomers' assets when they die, they've made debt inheritable.