I think that giving him a project car and parts is an acceptable solution. He would get to experience the joys and frustrations of restoring his own car, with his own hands, in his own way, just like the rest of us. However, even this solution has things we must consider.
First, the car has to be of sufficient quality/condition that any of us would want it (Exclude MoparClown from that). I know that goes without saying, but I just want to drive it home (No pun intended).
Second, if he has not had the resources to buy a project car, he probably won't have the resources to restore one, although he can just store it until he does, if that is an option for him. Does he have a place to store it/work on it? Does he live on base, or have his own house? Does he move a lot, or stay in one place? My brother-in-law is in the military, and he moves every two years, and it's always from one end of the country to the other. The cost of frequently moving a project car may be prohibitive for him, and he may wind up having to get rid of it. To me that would be very painful, because sometimes losing a dream is worse than not ever achieving it. The old saying "It's better to have loved and lost, than to never have loved at all", is not always true.
Giving him a restored vehicle, and giving him a project and parts are the two extremes, but maybe we can land somewhere in the middle. Although we may not be able to give him a restored vehicle, we may be able to take some of the steps, like fixing the frame, floors, trunk, etc. Maybe we could have the vehicle and/or body parts soda-blasted and prepared. Perhaps, we would be more successful by getting donations of services from individual service providers, in exchange for recognition and advertising rights. With people donating parts, time, skills, and resources, maybe our best hope is to fix some of the major problems and get it as close as we can. I'm sure he would appreciate anything we can do. Even if we could just concentrate on getting it safe and driveable, it would be a huge success. I'm sure it would mean a lot to him to be able to take it for a lap around Carlisle, no matter how it looks. If we can't accomplish any of that, at least we can fall back on giving him the project and parts, as is.
Don't forget to allocate some of the funds to transport the car and parts to Carlisle, then from Carlisle, to wherever he lives, or wants it taken. Maybe someone can donate transportation, and part of the funds could go for fuel.