From: Rabbi Moshe Sofer
To: Rabbi Moshe Perles
A man had publicly prohibited his whiskey to his brother due to the brother's drunkenness, but later exchanged the whiskey for dried fruits and wished to give those damaged fruits toward his niece's dowry. The Chasam Sofer rules clearly to permit, on three independent grounds: the prohibition was motivated by intoxication and dried fruits do not intoxicate; the vow may be annulled for the mitzvah of supporting a marriage; and the prohibition was directed at the brother personally, while giving items for his daughter's dowry is equivalent to feeding his children, which falls outside the scope of the neder.
Source: Shu"t Chasam Sofer EH II §154