Displaying related categories instead brands

The synchronization option will only work when you're displaying a listing of products or a listing of categories in the main area of your website. In that case, the module will use the parent category of these categories/products as basis for its own display of categories. The module will however ignore that option for brands.

If you want to change that behavior, you would have to implement the onBeforeCategoryListingLoad trigger via a hikashop plugin to modify the query loading the categories/brands (clearly not easy).