Agree with views already expressed about the difficulties in this. One other thing is that depending on the age of the material, the colors etc, may no longer be in style and less desirable. I have seen better luck in selling as bulk or scrap fabric by the bag or lb.
Sorry for you loss. I know I will face this when my mother goes. But I think she will have kits that she has purchased and never opened so those could maybe get 50% of purchase price.