I'd have written 'a huge smile that showed his front teeth were missing,' it feels more fluent.
The opening lines are good, they create tension and raise questions of who this man is and how he comes to be brawling. His relationship with his brother is plausible and you convey it well.
Overall your descriptions are good. Just one thing, 'clutched' the guitar would be better than 'engulfed.' If you engulf something you cover it completely. One hand would'nt cover the whole guitar. Otherwise well done.
Children will probably like how the parrot goes from zero to hero. It would take more than 20 parrots to right the ship but you're using a surreal premise all along so you might get away with it. Its a nice twist at the end.