Hang in there! Without being there, I can't tell whether they turn brown because of the mildew or the medicine. Leave the fruit on the vine. It will draw juice and life, and probably mature.

George

All the leaves are wilting or just the ones that had powdery mildew? I used a fungicide for the first time this year and for me any of the leaves that were covered with powdery mildew were the ones that died. For me the leaves were already yellowing and were pretty much covered with the mildew so I convinced myself that this was normal since the powdery mildew was feeding off the leaves and the leaves were on their way out anyway. As long as the growing tip is still healthy and green you shouldn't worry about your pumpkins.