A confederate is an ally — someone who's on your side. Your brother, the artist, might be your only confederate in your goal of studying modern dance in Paris this summer.
A confederate is anyone who supports you and works toward the same goal with you. When it is used in the context of government or politics, it means "united by a treaty," like two countries that have joined forces against a third. When the first letter is capitalized, Confederate refers to the southern United States during the Civil War, which were confederates in their fight to secede from the rest of the country.