Dream about my long deceased mother

New to Reddit but I need help interpreting this dream. For backstory, my moms been gone for 31 years. I stopped having dreams about her shortly after she died because I was so bereft upon waking up, realizing she was gone and it was just a dream. The last one I had of her she told me she wouldn't come to me again in dreams because of how it affected me. I don't recall any other dreams with her until this morning.

In my dream, my brother was moving a casket into a room, but one of the side panels opened (where the handles are) and I thought I saw movement. My uncle gasped and said something's moving in there. Family all around, the casket was opened and my mother was laying there, her arms contorting and writhing. She had bandaging on her face, like cotton and a mask of aluminum foil. (She passed from cancer and was not bandaged at her real funeral). She tried taking it off and I whispered no mom. You have to leave that on. She calmed down, but her hands and arms still contorting like she was in pain. I remember my dad (also passed) being there, as well as all 4 of my children (all alive). My daughter and I don't speak in the waking world but she was kind to me in the dream. That's a whole other story. In the dream I went to the casket and leaned in close and said "mom I really miss you. It's been so hard all these years without you". She whispered something but I cannot recall it and it makes me sad.

Can anyone help me figure out my dream? I have minor stresses in life and a few regrets but I cannot think of anything that would have triggered this dream.