We are all different, I have slept with one lady who took ages and ages to 'lubricate' enough for intercourse, and another who would be seriously wet within thirty secondds, and continue thus right through!
Personally, I would not have a problem with excessive moisture, although I understand how your friend feels.
My advice would be to relax and enjoy herself - too much is better than too little in this situation, and if a guy is put off or offended by her biology, she is with the wrong guy!