Re: child's infected tooth
Infections in the mouth are always something to take care of immediately. The warm moist environment of the mouth, and the bacteria that comes with eating, are a perfect place for infections to set in. With the jawline being so close to the brain, these infections can turn ugly fast.
About the braces, they have many solutions for "holding" space, or whatever is required to achieve the desired result. My son just got out of braces, and he had a childhood root canal on his front tooth. They kept the tooth there while the braces were on. Then they pulled it, and it is now being held open with a fake tooth right in his retainer. He has to wear the retainer anyway, until time to have a permanent implant done.
Get that infected tooth out first thing...The rest will take care of itself. I hope that helps..