Traditionally, I as backer up in chief have made multiple family photo backups. But in each recent years the newer phone cameras take larger and larger images. My wife's photo collection for 2016 was as large as the previous ten years combined.
If the trend continues, cloud will be the only sensible solution.
I just re googled some of the Apple stories where they want the dearth cert, the will, the original purchase receipt of the device AND a court order to unlock after someone has died suddenly without passing on their Apple id
E.g.
http://gizmodo.com/mother-bequeaths-...-it-1537274680