Oh my @hbjuniperflat that must have been distressing and scary for you. I hope you saw the helpful suggestions from @teacher502 and @providence1960.

I hope night time driving is relatively easy to avoid for you both.

Providence, I found it interesting that your mom actually found it to be a relief to be in the back seat as it relieved her of the pressure or stress of watching the road. Juniper, that might be worth a conversation with your husband about offering the backseat option. This may be best approached if you have others with you so that it's not banning him to the backseat alone.

I'm grasping at straws here, but I wonder if there is something else that you could use to occupy him while you're driving? Some of these things may not work depending on his state of mind at the time or the length of the drive, but here are some thoughts I had:
- Ask him to read the highway signs or street signs
- Play "I Spy"
- Read license plates
- Ask him to watch out for particular milestones or sights to "help" you navigate

What might help focus his mind on something other than co-driving?