In some places you can hear the expressions:
¿Qué te pasa, mi amigo? or ¿Qué te pasa, mi hermano?, but I'm not pretty sure if they are grammatically correct. In Spanish, when you speak with someone and call him "amigo" (e.g. "Hola, amigo", "¿Qué haces, amigo?"), it is supposed he is your friend, so that if you include a possesive pronoun is because you want to emphasize it.