Wa Alaikum As'salam,
There is no proof that they've never been to Egypt. And one can easily say something about a place even if he/she never visited it, especially if the common people's experiences and opinions about the place are the same. People formulate stereotypes
based on patterns and experiences. For example, you can tell an individual to not go to a certain ghetto area, because it has high crime rate and he'd be in grave danger. You don't necessarily have to experience this danger yourself, or lose a loved one, to formulate this opinion. You can formulate this opinion based on a
plethora of solid facts, patterns and experiences from other people. The same can be said about a prosperous and safe place. Everyone in the world
wants to migrate to the USA because it is a land filled with the greatest opportunities, and it is technologically the most advanced country on earth. Yet, the vast majority of them have never been here before.
In any case, I trust Allah Almighty over their conjectures and lies. Also, if Allah Almighty said it in the Glorious Quran, then this means the Almighty has inspired the parents to say it. I trust the Glorious Quran. It is the only True Divine Book of Allah Almighty on earth today. All else are corrupt. The Glorious Quran is filled with scientific, numerical, historical and archeological miracles that prove its Divinity as Allah Almighty also said in the holy Book:
www.answering-christianity.com/ac20.htm#linksSo I'd take the Holy Quran's account over anything else.
Take care,
Osama Abdallah