You can’t use Islamic theology when talking about Catholic theology. It just dosen’t work. I know in Islam you believe Jesus is just a man, but please at least meet us Catholics halfway when speaking to us. I always make sure to study Islam more so I can better understand Muslims, and I try to use Islamic theology - at least when I remember to, most of the time I forgot - when speaking with Muslims. Please return the kind gesture. Read the
Catechism of the Catholic Church to learn what we Catholics believe and use Catholic theology when speaking to Catholics. If you want to be understood by a man who speaks French, you use French to communicate with him; the same goes for theology: Islamic for Muslims, Christian for Christians, etc.
In Catholic Theology, the Father and the Son are One in light of the One Nature of God. God is not physical but spiritual. Jesus is God and Man. He is the Son in the flesh, God Incarnate. Hence, He says, “I and the Father are One.” For more on the Holy Trinity, read the Catechism.