a judge bases his or her decisions about child custody based on income?

my brother came illegal from my country the police stop him send him to child foster and now he is applying for juvenille petition because he cross the border as a minor I have court for child custody because I am his only relative here. however I had. charge against me for assult and sexual harrasment but this charges were taken out already will this affect me for the custody of my brother. Also, I make low income and I have a son and family ton support will the judge ask me for prove of income that I have the means to support my brother?