Dreaming of a deceased loved one, especially a parent, can be quite emotional and may evoke strong feelings. The imagery of your mother in a coffin could represent several things.

1. Processing Grief: If you have lost your mother, this dream might be a way for your subconscious to process your grief. It could signify that you are still coming to terms with her passing and the emotions associated with it.
2. Fear of Loss: If your mother is alive, this dream might reflect a fear of losing her or anxiety about her health. It may indicate a need to cherish your relationship with her.
3. Change and Transformation: Coffins can symbolize endings and new beginnings. This dream might suggest that you are going through a period of change in your life, and your mother represents guidance or support during this transition.
4. Unresolved Issues: If there were unresolved issues or feelings between you and your mother, this dream could be a way to confront those emotions, seeking closure or understanding.

Reflect on your current life situation and emotions to gain deeper insights into what this dream may mean for you. If the dream continues to trouble you, consider discussing it with a trusted friend or a professional who can provide further support.