Does she have scraps of the fabrics? I would mark them with the orange chalk, then try various methods of getting rid of the marks.
The problem you have is with the dye in the chalk. When dried, the area became an orange tint because the dye dispersed in the fabric. You need something that will actually remove the dye.
What I would try is using a soft toothbrush to rub in a mixture of Synthrapol and water, followed by thorough rinsing. Synthrapol is supposed to be used in hot water, so this may not work. I'd try it, though, because Synthrapol is designed to suspend unset dye particles in water to be rinsed away and that is exactly what you need here.
If the quilt does end up needing to be washed, I would definitely wash it in Synthrapol.