Even though what you did was tricky, you did it for good reason. I mean, ya could've hid the car!!
Your dad was being irresponsible and it obviously was the only way to possibly save lives and his life. I wouldn't feel guilty. I don't think there was much else that could be done with him being obstinate and all the bickering going on.
My dad's eyes were getting bad and we had to take the car away! He was going to drive come hell or high water. He needed eye surgery before he could drive again yet he drove anyway.
His feelings were totally hurt over this. So, IMO, it would've been easier if it were a pair of glasses being thrown away. I'd relax. Drive him to the eye doc and he'll be very happy in the long run and so will everyone else!