Combine the berries, sherry, lemon juice, and lemon zest in a bowl; toss to blend. Set aside.
Beat the heavy cream in a large bowl until soft peaks form. Gradually beat in the sugar until stiff peaks form. Refrigerate cream until needed.
Cut pound cake into slices 1/3 inch wide, discarding cake ends.
Assemble the trifle by placing a layer of cake slices in the bottom of a glass serving bowl. Spoon half the berry mixture with juice over the cake slices. Cover with half of the whipped cream, and sprinkle with half the coconut. Repeat layering with the remaining cake slices, berries and juice, whipped cream, and coconut. Refrigerate at least 1 hour before serving.