So glad you joined the board and so sorry for your loss.
I recently finished 6 quilt tops that had been made my friends grandmother. It was mostly old clothing and he recognized his mother's dress, his dad's work shirt, etc. He gave each of his siblings one and kept one for his son. I think they are priceless memories and was happy to be a part of preserving them.
So my vote is...finish them. However, I have no experience or comment about the silk top!! :)