Why is bud crying the night he ate dinner at a restaurant with the jazz band?

Bud is crying the night he ate dinner at the restaurant with the jazz band because he feels a deep sense of loneliness and longing for connection. Surrounded by the lively atmosphere and the music, he is reminded of his past and the family he has lost, highlighting his isolation. The experience stirs up emotions as he grApples with his desire for belonging and the harsh reality of his situation.