Recovering from grief and depression may never happen. Some pain may discolor a person's mind and spirit for the rest of his/her life.
Please let your hurt go.......she told you she loved the quilt and she did. Your mother did not give away your love with the quilt. The sadness or misery eating at her prompts her to poor decisions that probably, unknown to you, hurt her more than anyone else.
Discarding cherished objects can be a sign of withdrawal from life, either figuratively or literally. Keep a loving eye on her.