The Intel® Dual Band Wireless-AC 8260 and other current Intel wireless adapters are designed to be used mainly as WiFi clients, for basic Ad Hoc usage, or with the mobile hotspot feature of Windows® 10.
Also, Intel® Wireless Adapters comply with international regulatory limitations. Using 5 GHz may not available in order to comply with these regulations.
We would like to add that you should check on this with the http://www.intel.com/content/www/us/en/support/topics/OEMs.html Computer Manufacturer Support. The driver or software for your Intel® component might have been changed or replaced by the computer manufacturer and your adapter may include specific features or customizations made by the OEM.
Furthermore, Intel does not provide nor supports any tools used to enable hotspot functionality, you might want to contact the software provider as well.