Without being able to see the garment on the person, it's difficult to tell you what to do because the blouse not fitting in the front can actually be due to not enough room across the back of the shoulders. That is, there isn't enough fabric across the shoulders in the back (because of her wide shoulders), so the garment is trying to "pull" more fabric to the back to cover the shoulders and the front doesn't fit.

My best advice is to check a sewing fitting book (the library or even take a look at a book in the book store).

The Vogue sewing book has some good photos of where wrinkles show up and what causes them and how to alter the pattern. Fit for Real People is another book, with very detailed instructions on how to alter the pattern.

However, identifying the actual cause is important.

CMC