it will cost a little more, but Spoonflower will give you the best images. You don't say what the fabric is that you plan to use, but I get the impression it's not cotton? I'd use cotton just so you don't have to stablize it and also because I think you will get better (more lasting) printed images.
As far as washing--I would never dry clean a quilt(unless maybe it was wools and silks) but would inform your son that it would need to be hand washed--so he best not treat it roughly!