ISO sensitivity in Red cameras

Please please please somebody help me understand something totally confusing..

Basically I understand sensor sensitivity changes through iso selection to be a physical, analogue change before conversion to digital realm. My friend told me you need not worry about iso selection on red cameras as it can be changed afterwards like white balance etc. The latter I totally understand as the image file contains all the information necessary to change picture styles and colours as RAW does not compress this information into a smaller file.

However like I said, ISO as far as I understand is not flexible post production as it's a real physical change in the sensor (increased charge to component? Hence quicker battery depletion with higher settings...)

On a few forums I've found information confirming what my friend has said though so HUH?? So confusing. And I can't appear to find information on the specific way sensor sensitivity is changed from a scientific point of view...

Please can somebody help me understand?

Thanks so much