1) How much time did she spend outside the US on her current trip?
2) Did she have any trip in the last 5 year that was longer than 6 month?
3) How many days did she spend in the US in the last 5 years?
4) How long did she have GC for?
The reason I am asking these questions, you are focusing on exam etc, but she may be not even eligible to get citizenship as of today based on her travel.
On a side note, getting N-648 approved is not simple, even with a lawyer. You need a lot of medical proof over extended period of time. It is a lot easier getting exceptions listed below for English language part:
- Age 50 or older at the time of filing for naturalization and have lived as a permanent resident (Green Card holder) in the United States for 20 years (commonly referred to as the “50/20” exception).
OR
- Age 55 or older at the time of filing for naturalization and have lived as a permanent resident in the United States for 15 years (commonly referred to as the “55/15” exception).