Just a word of warning to anyone who's getting misty-eyed about the “unlock my dead loved-one's phone.”
You're not going to find a novel they were writing, it won't be their last thoughts of the summer vacation your family took way back when, or whatever warm fuzziness you're looking for as closure.
You're going to find porn.
Because a smartphone is just a handheld computer, and ask anyone that works on them, if you go digging, eventually, you'll find porn.
So, stop asking Apple, Google, whoever to unlock someone else's phone. It's a no-win situation. Whatever you find there won't ease your grief, but it might lead to additional problems.