Both of her parents speak and understand English - they just have very strong accents, and are still more comfortable in Italian.
I don't understand some of the comments - losing an accent and becoming comfortable in another language differs from person to person. I have a close friend who is Israeli - originally, that is. She has been in this country since her very early 20s - and has been an American citizen for at least 30 years. She is fluent in English - she learned it as a child - but to this day, she still has a VERY strong accent. For some reason, she has hung onto it, despite being married to a native-born American, raising 3 children and 6 grandchildren, and speaking English daily for over 40 years.
If her husband, children or grandchildren were fluent in Hebrew, she probably would speak it more often, but she does not. However, she is still hard to understand. By the way...she is extremely bright, and works in a very technical job which requires her to communicate with many people daily. Somehow, despite her accent, she manages to communicate very well...