Thanks for the input. Rick already has the lift which is used to transfer him from the bed to his chair, bath etc, that is not a problem. The problem is Rick is in Texas, I am only going to be at his home for a couple of days and I won't have time to fab something while there. I have been in contact with Rick, he has explained what is needed to support his body, basically he just needs to be strapped into something that will keep him from falling forward, backward or sideways.
This is something that is only going to be used ONCE while on this trip and if it works maybe sometime in the future, I won't be taking the sidecar off the frame. Thats why I am thinking a simple frame made from conduit that can be placed in the sidecar would be simple, cheap and easy. I don't have any of the tools needed to work with bending conduit.