What to know Islam states that Jesus was born of a virgin, without a human father (Sura 19:20)...But Islam also claims that he's not the Son of God (Sura 4:171, 5:17).
Muslims believe that the example of Adam shows that the Islamic theology is accurate: That God can create a being without giving this being the title "Son of God.
What to say:
Read Romans 5.
How is Jesus like Adam? How are they different? What does this mean for us as humans?
Read Luke 1. How was the birth of Jesus unique?
Read John 8, with emphasis on verse 41.
Why did the Jewish leaders claim that God is their Father? How did Jesus respond to this? Notice that the concept of a human referring to God as "Father" is not an issue of blasphemy: This is how Jesus taught us to pray. This is also the promise he gives to everyone who receives forgiveness through him....This is how Jesus described the reconciliation (renewed relationship) made possible with God through Jesus's death on the cross. Read John 1:9-14 and discuss.
Read John 8 again, this time with emphasis on verse 59.
Why did the Jewish leaders want to stone him? Notice that they realized he wasn't using the phrase "son of God" to refer to genealogy leading him to Azzam (Adam), or even Ibrahim (Abraham). They were angry because they realized he was claiming to be God. Listen to how your friend engages with this. Is their concern the question of Deity? If so, the comparison to Adam is an irrelevant issue...No one (Christian or Muslim) claims that Adam is God. This is an assertion completely unique to Jesus.
Read Ezekiel 34 together with John 10. What promise did God make?
Read Matthew 16:13 and 20:28.
Although Jesus is often referred to with the title Son of God, he often referred to himself as the Son of Man. What does this mean? Read Daniel 7:13-14 together. In this vision, we see one like a "Son of Man" receive worship. Although Adam was also created without a human father, he could never receive worship (Luke 4:8). Later, in the revelation given to Yahya (John), we see another vision described. Read Revelation 5 together. Prayerfully seek to understand these passages.