It sounds like your dream is rich with imagery and emotions. Here are some interpretations to consider:

1. Baby Symbolism: The presence of the baby girl could represent innocence, new beginnings, or something in your life that is in its early stages. It might symbolize a new project, idea, or relationship that is developing.
2. Family Dynamics: Your mother and brother's presence indicates that family is significant in your life right now. The way they are positioned may suggest a feeling of connection or perhaps even a desire to communicate more openly with them.
3. Couch as a Place of Comfort: The couch can symbolize comfort, relaxation, and safety. Being in a relaxed position while interacting with your family may signify a desire for harmony and support in your relationships.
4. Laughter and Joy: The baby's laughter could reflect a sense of joy and playfulness that you may be seeking in your life or that you associate with your family or childhood.
5. Blocked View: The baby blocking your view of your brother might signify feelings of being overwhelmed or distracted by something new or innocent in your life, potentially affecting your relationships with others.

Consider how these elements resonate with your current life circumstances or feelings. Reflecting on your emotions during the dream and upon waking can provide further insights. If the dream felt particularly significant, it might be worth exploring any new developments or changes in your life that relate to family or new beginnings.