HTC One PN07200 *Assistance Needed*

Hi! First off I would like to thank anyone in advance for stopping on by my post. Any help in the following situation would be GREATLY appreciated!

My best friend passed away recently in a motorcycle accident and I am left with his HTC One PN07200. I am desperately trying to access his phone without losing any data so I can recover photos/texts for myself and his family. I was wondering if anyone can point me in the right direction to unlock it as I have tried every attempt for unlock codes and his gmail account that is linked to the phone. Plugging in a usb to the PC has no plug n play reaction. I was reading a bit online about a possible "rootkit" or "rooting tool" that would accomplish an unlock without data loss but I am sorta at a loss at what approach I should take. I found this forum and saw lots of tools and other discussions about unlocking phones and such but wanted to ask the community first. If you can assist me on this situation it would be greatly appreciated.

Thanks a bunch!