Thank you for sharing your dream. It appears to be rich in symbolism and reflects various aspects of your life, including family dynamics, memories, and perhaps feelings of loss or connection.

1. Family Gathering: The dream begins with a family meetup at a restaurant, suggesting a desire for connection and reunion with loved ones. Since you mentioned that your first husband is deceased, this gathering may symbolize your longing to reconnect with family members and perhaps to process feelings surrounding your past relationships and losses.
2. The Restaurant Setting: Restaurants often represent social interactions and shared experiences. The fact that the restaurant was quieter may indicate a desire for peace and meaningful conversations within your family. The tables being set up back-to-back could symbolize both unity and separation within family dynamics. You may feel connected yet distanced from certain family members.
3. The Black Dog: Dogs in dreams often symbolize loyalty, companionship, or aspects of oneself. The escaping dog could represent something you feel is lost or needing attention. The fact that you managed to get the dog back initially may reflect your ability to maintain control over certain aspects of your life, but when it escapes, it could signify feelings of anxiety or loss that you may be experiencing.
4. The Walk to the Restaurant: This scene with the canyon and the shops represents a journey you are taking in life, filled with both risks (the canyon) and opportunities (the shops and restaurants). The bright, sunny day suggests optimism, but the specific details indicate a blend of familiarity and new experiences.
5. Interaction with Family Members: Your brother's new possession that you recognize but your mother cannot see could symbolize differing perceptions within your family, particularly regarding experiences or feelings about the past. This may imply that while you are aware of certain truths or memories, others may not see them in the same light, especially when it comes to your deceased loved ones.
6. Seating Arrangement: The seating dynamics can signify your role within the family. Sitting at the end of the table facing others suggests a position of observation and perhaps a feeling of being slightly apart from the group, which may reflect your feelings of being an outsider in your family or needing to process your thoughts and emotions before fully engaging.

Overall, this dream seems to encapsulate your feelings of connection, loss, and the complexities of family relationships. It may be beneficial to reflect on your current relationships and how they relate to your past, as well as any unresolved feelings you may have regarding family dynamics or your first husband. Engaging in open conversations with family members about your feelings could also provide clarity and healing.