If your friend is a Catholic then I am sure you will get a long list of supposed contradictions since the vast majority of Catholic doctrines contradict the Bible. Catholicism is a doctrine driven faith, not a Bible driven faith. Christians have been responding to atheists as well as Muslims concerning alleged contradictions in the Bible since at least 1084 A.D. Therefore when you get your list check out this site:
http://answering-islam.org/Bible/Contra/index.html
http://answering-islam.org/Responses/Os ... ctions.htm
Jesus instructed us to preach the Gospel of the Kingdom to the whole world. His instructions include leaving those who reject his message alone. Islam on the other hand instructs Muslims to force conversions and/or extort those who reject Islam, or just kill those who reject Islam.
Can a religion be proven false? Yes and no, we can show that Muhammad plagiarized Christian myths by claiming these myths were received from Allah and are therefore included in the Qur'an. Compare Sura 2 with the Infancy Gospel of James (Protoevangelium of James), which has has been shown to be have written long after James died and is not even accepted by the Catholic Church who has a vested interest in proving it is authentic.