I think its not possible to be primary caregiver without a photo id card...
You are really a caregiver for your uncle???
As far as I know, the application requires ONE person (Select One!) to possess plants - on the application it says:
"Section C: PERSON ALLOWED TO POSSESS PATIENT’S MARIHUANA PLANTS: (REQUIRED)
SELECT ONE:  APPLICANT/PATIENT OR  PRIMARY CAREGIVER (Caregiver Attestation & photo ID Required)"
They will not even consider your CG application if you select "Applicant/Patient", as the patient will be responsible for obtaining and cultivating marijuana. Your patient card will say "NO Caregiver" and that you may "possess plants". If they process your Caregiver application - your card will say "NO" for possessing plants, and the back of the card will have your Caregiver information and say the caregiver may possess plants. Cops looking at "who may possess plants" will see either you or the CG may possess plants - not a patient that grows, but has a CG. The card only allows one or the other - you either get the patient card "possess plants' or you get a CG on the back of your card, who possess plants. Remember - police are just going to read the card - not interpet your little deal with CG.
If this poster has new information - proof that this is legal and accepted by the MDCH - then I concur.
So your uncle may face problems though...
I think you have got points... clear to you...