Could anyone assist me with how to remove car from my parents' possession for their safety, as well as those around them? Safety is at stake!

Get their driver's license suspended by the state. In my state, you can either do this or have their doctors do this. There was an online form to fill out and the online help desk was helpful! It gave my MIL 30 days to challenge the decision. Her comprehension is low enough she didn't understand what she needed to do. She would either have to have a doctor fill out an OK to drive form, appear in court or retake the licensing test. We had tried to tell her that since she'd also had a few loss of conscience states, that she should not drive as she could have an accident and kill a child or be sued for all she was worth, but when she did not cooperate or "forgot" she was not supposed to drive, we removed the keys AND had her DL suspended permanently.

Take the keys! If you know where all the keys are located, you can take the keys away. You don't have to admit to this. My MIL pestered my husband to give her back her keys numerous times, so we also suspended her license.

Removing the car from her property has proven impossible. She seems to need to see it. When it "goes to the shop for maintanance" or we borrow it to replace the car that is in the shop, she bothers us to bring it back until we bring it back. Then she reminds us that we didn't leave her the keys and we start that whole cycle over again about not being allowed to drive.