Caregiver Status Question

I am a medical marijuana patient in California. I want to designate a friend of mine as a caregiver, but I'm not sure how to go about doing that. I did some searching online and found forms off of a webpage to donwload, allowing me to designate someone as my caregiver, but I was wondering if thats covered under the law? In other words, if my friend gets busted for having pot on him, and he shows them the form giving my permission for him to be my caregiver (Along with a copy of my doctors recomendation and doctors card that I gave him), undet the law, can he get in trouble? Is there some sort of specific process or method I need to go through to designate someone as caregiver?
If no one knows, I'm seeing my doctor on the 31st, so I'll post what he tells me.
-PM