My brisket is too sweet
You can probably get rid of much of the wine and its sweetness by removing the brisket from the sauce, and possibly rinsing it (at some cost to flavor).

This may leave you with an under-flavored brisket; you could try putting it in a flavorful (and maybe spicy, if you like that) tomato sauce to give it some balance.  Acidity tends to cut any remaining sweetness.