Trigorin

Character
Trigorin Hufnagel was Grandma-ma's husband, and the father of Bernice, Beatrice and Beverly. They were from the same town in Russia. After Grandma-ma's true love, Petrov died in the war Trigorin saved Grandma-ma and her family from a fire and brought them to America with him. The two were married and opened a candy store together. However, Petrov soon returned revealing that the fire was started by Trigorin, who had purpossly trapped Petrov inside the burning house to get rid of him. Petrov challenges Trigorin to a duel, however they both end up firing into the air instead. The bullet from Trigorin's gun hits a blimp, which crashes to the ground killing both of them.

In other episodes Duckman mentions having met Beatrice and Bernice's father, and Beatrice also mentioned her father when she first met Duckman. Therfor, it stands to reason that Grandma-ma was re-married at some point.