My name isXXXXX a licensed attorney. I am honestly sorry for the circumstances, very much appreciate your patronage, and am glad to try and help out.
I do have direct experience handling guardianship matters, so here's how this works. The Court will appoint an attorney ad litem to represent the proposed ward. This will be done automatically, without charge, and can't be waived even if that person or any other party for some reason wanted to skip that step. This attorney will be charged with the responsibility of speaking up for that person, making known their desires, and ensuring that proper procedure is followed throughout. There is a natural tendency to go with the closest relative, which would be the brother here. However, that is not at all a "given". Rather, the Judge will make the decision pursuant to a legal standard known as what is "in the best interests" of the minor. That standard, and only that standard, will determine the final outcome. And if the aunt is more stable, lives locally, and overall better suited than the brother to serve in this capacity, then she would be appointed. It all rests with the discretion of the Court, guided by the input of the ad litem and any experts who may be consulted (i.e. physician, counselor, etc.). But, I can certainly say that in light of the brother traveling basically half of the year, if bets were being taken, my money would be placed on the aunt.
If you have a follow-up question or need clarification, please just say the word by using "reply" to reach me.
I truly hope all works out for you and all concerned.