Oh - I feel your pain. I had the problem at the upper end - with a broken neck in one of those halo's I had to try to slide into every vehicle head first and sideways. Top down would have been all right, but we didn't have the roadster back then. Otherwise it didn't matter what I was trying to get into - I had a hard time trying to fit. Getting out was equally hard, and once in a car the comfort was non-existant. Take care and don't travel more than you have to. Physio-therapy is also misleading. That therapy part sounds like it could be comforting. Don't let it fool you.
I have to agree with Spark, though. Maybe your son didn't want the jeep to start. (But where would we be without our kids!)