Here's something important. If your child is a minor, you should know the codes to access the phone. You should be tracking what your child does on their device and making sure they're safe when they access the internet. Smartphones are *Computers* and therefore you should monitor a child's use of them exactly as you would their use of a PC.
The story of this man is tragic. He lost a child to cancer and now cannot access the cellphone to get the photos from it. This is truly a sad tale. But the tragedy of one man and his loss does not in any way suggest that the rest of the world should have the security of their devices compromised. What this man wants is no different than what the FBI is trying to force Apple and Google to do.
We live in a society that in which there are countless cases such as this. Someone suffers loss, wants access to the information of those they've lost. But here's the simple truth. If you don't put it in your will, or in some way make sure that all that information is transmitted to those you love in case of your death, that information is gone forever. Digital is ephemeral. This is the same reason we are constantly telling you to make sure you back up your computer and especially all the important files you have on your computer that you do not want to lose.
When I leave this mortal realm, I will make sure someone has access to my digital lockbox. But other than that, when I'm gone, my digital data will more than likely go with me. This is just the nature of digital footprints. Eventually the tide washes over them and the sand is bare again.