How do I take my mom drivers license away due to Alzheimer's?

Just want some feedback for mom with AD who hasn't drove in over a year( I won't let her) Told DMV last Aug about her AD and again in Nov they never sent anything so I kept putting mom off about diriving. Mom's DL is up for renewal ( she is 83) and she wants to renew( have to so only in person if over 79 here) I called DMV and they have her DL flagged when she goes in to retest her and let the field personel decide. Should I take a chance and let them tell her no so it can finally be over with What is she has good day and they give it to her? Dr wants the state to take it away and told me to send them letter rather than him. I feel like no one wants to help me put this to rest with her. Any other suggestions?