Here's my thinking on this. You either need the platform of the dolly to rotate or the car's front wheels free to steer. You can't have both... For your test next week, lock the steering wheel as noted with a strap or such and leave the dolly free to swivel. Or, you can leave the steering "unlocked" and put the pin back in the dolly. (I suspect the mfg would strongly recommend against this as I don't believe the pin and seat are designed to deal with the shear loading)If you do the latter, be sure to check clearance between the dolly fenders and the side of your car.
My understanding is if both dolly and car are free to "steer", the car may well drift left or right. This is the situation I believe you had.
Just my two cents and may well be way off base!!
Sorry for the passing of your friend.
Good luck,
Gary
