:bism: (In the Name of God, the Most Beneficent, the Most Merciful)
(Peace be upon you)
Sister, either your friend has misunderstood what the teachers are teaching or some really bad teachers are giving lectures in this so-called "islamic school."
There is zero way a person can understand the Qur'an without the aegis of
ahadith (prophetic traditions); if a person rejects
ahadith (prophetic traditions) altogether, that person essentially becomes a non-Muslim and would be characterized that way under
shariah (Islamic law).
Frankly, what's more likely to have happened is that your friend has learned some
ahadith that she didn't really like due to finding them facially harsh (without learning as yet context) and in the process of learning that there is a possibility that some
ahadith can possibly be characterized as weak, she thinks she's found a loophole to reject them altogether. However, even some of the weak
ahadith are characterized as such due to the chain of transmission and not because they're not true. I fear for your friend's
iman (faith) and I ask that you pray for her and do not let her influence you in this matter because she's not even 1% correct.
:wa: (And peace be upon you)