Dreaming of a deceased loved one, especially a parent, can be a profound experience. In your dream, your mother asking you to "open the door" and "where is the key" may symbolize a desire for connection or communication. It could represent feelings of longing for her presence and guidance in your life. The door might symbolize a barrier between you and her, or perhaps a new phase in your life that you are hesitant to enter.
This dream may also reflect unresolved feelings or memories related to her passing. It could be an invitation to explore those emotions and find ways to honor her memory. Consider what the door represents for you—opportunities, memories, or feelings of grief—and how you might "open" that door in your waking life.
Reflect on any current challenges or transitions you are facing, as this dream may provide insight into your emotional state and the support you seek. It might be beneficial to engage in activities that help you feel connected to her, such as journaling about your memories or talking to someone about your feelings.