" He wouldn't be grinning like a proud rooster then."This means that Tio Luis would not be grinning and proud, once he realized that Esperanza and mama had left. Instead of being proud,he would be mad and angry.
" After you have lived many mountains and valleys, we will be together"This means that Esperanza must wait and be patient. Soon Esperanza, Mama, and Abuelita will be united as a family again.
" It looked as if someone had taken a gigantic comb, dipped it in paint, and gently swirled it around on a huge canvas."This means that with the darkness in the sky, and the bit of moonlight it looked liked the entire sky was painted black, especially since everything was burnt.