Wherever you saw this, is immaterial, its self selecting, the families who found "closure" post, the ones that don't, well, don't.
Its also a bit odd, as most people executed in the US have been awaiting their sentence for many years, even decades.
Anyway, as pp have said, the death penatly shouldn't be introduced because of the victims families wishes.
TBH the more i read through this thread, the more i think maybe we have got the balance right with Whole life Orders.