Get the tyres up to pressure and see how the carcass is. Again, the perished rubber doesn't matter - it's the nylon belts that contain the pressure*.

They usually don't take too kindly to being left with a fold in em for ten years, but it's worth a shot.

*I have a tyre here that's so perished, a small piece of the tread here and there has parted company with tyre, and it's happily holding 120psi. It's fine.