Your dream seems to encompass themes of validation, self-perception, and family dynamics. Let's break it down:

1. The Casio Watch: The watch may symbolize your desire for approval and validation from others, particularly from your friend who is knowledgeable about watches. Feeling embarrassed and regretful about it being fake suggests you may be grappling with feelings of inadequacy or fear of being judged for your choices. The question you posed to your friend—whether he still liked it—indicates a desire for acceptance despite the perceived flaws. This part of the dream could reflect your own self-esteem and how you value external opinions.
2. The Empty House: Houses in dreams often represent the self or your personal life. An empty house with minimal furniture might suggest feelings of emptiness or a lack of fulfillment in certain areas of your life. The fact that you are with family implies that these feelings may relate to your familial relationships or your sense of belonging.
3. The Minecraft World: Transitioning into a Minecraft world could symbolize a desire for creativity and exploration, but feeling claustrophobic may indicate that you feel trapped or restricted within your current reality. This part of the dream points to a struggle between your imaginative side and the limitations you perceive in your waking life.
4. Your Brother: The presence of a younger brother you've never met could represent new aspects of yourself or potential you have yet to explore. This could indicate a longing for connection or a reminder of childhood innocence and the dynamics of your family structure.

Overall, this dream suggests that you may be navigating feelings of self-worth, the need for external validation, familial relationships, and personal growth. It might be helpful to reflect on these aspects in your waking life. Consider what changes you can make to feel more secure in your self-identity and how you relate to your family. Additionally, engaging in creative or explorative activities could help you address feelings of confinement.