She's topo old for it to be adolescence in the normal sense, dealing with hormone, and all that. So it is all behavioral, from the sounds of it. Can your brother walk her at all? Is there any fences area nearby you could let her run for a while every day? As for her pulling on the leash, what kind of collar/harness do you use? A halti might be a good investment. Most of all, consistent training, especially when walking, and outstubborning her in her training is most important.