While Adobe claims on its charts that the 9.3 RAW update plug-in for Adobe Photoshop CS6 (Extended) works to convert RAW files directly from the Sony Camera RXRII, it does not. Perhaps my MacBook Pro OSX El Capitan 10.11.5 exceeds the 10.11 noted on the Adobe Camera Raw chart?
CS6 can only be updated to a maximum of ACR 9.1.1 so attempts to install ACR 9.3 in CS6 will fail. You can verify what version you have by doing About Plug-in / Camera Raw (I think on a Mac).
You can sign up for CC (LR+PS@$120/yr=$10/mo is the cheapest) or use the DNG Converter to make DNGs from the raw files and those DNGS, but not the native raws, will open in your older software.
The DNGC is here: http://www.adobe.com/downloads/updates/