Lol! He's like my older son. I had to do a dry run in the truck with him for him to believe me that he'd be really snug and safe.
ETA: You're going to LOVE the Travel Vest! You'll look forward to the day that your younger child can get one and you can feel FREE again! My younger DS still falls asleep in the car on any trip over 30 mins, so we take a fluffy pillow to fold in half and stick between his head and the door (or his head and DD's car seat) so that *I* don't get a crick in my neck looking at him.