Be Kind
I would repair, fix and use it, if not in the quilt, maybe in a one block wall hanging.
But I would pm them also and kindly give them suggestions on how to do a better outcome on their blocks. We all had to learn and lets face it, it take practice to get better, but if no one tells us we have to get better we would keep on going the way we quilt and never ever become better.
But always in a kind way.
Robert