here is some info you father might be able to use.. thrid paragraph has a reference that might be usefull
by AllAboutGOD.com
God-sized Reality
Foundation of the Christian Faith
What is the Trinity Doctrine? In a nutshell, there is one God, eternally existing in three persons: Father, Son (Jesus Christ) and Holy Spirit. The three persons of the Godhead are coequal and co-eternal (Genesis 1:26, Isaiah 9:6, Matthew 3:16-17; 28:19, Luke 1:35, Hebrews 3:7-11, and 1 John 5:7).
How Can We Comprehend It?
The most difficult thing about the Trinity Doctrine is that there is no way to adequately explain it. The Trinity is a concept that is impossible for any human being to fully understand, let alone explain. God is infinitely higher than we are, therefore we should not expect to be able to fully understand Him. The Bible teaches that the Father is God (Exodus 3:14), that Jesus is God (John 8:58), and that the Holy Spirit is God (Acts 5:3-4). The Bible also teaches that there is only one God (Deuteronomy 6:4; James 2:19). How these two statements of doctrine can both be true is incomprehensible to the human mind. However, this doesn't mean that they're both not true.
No Illustration Is Completely Accurate
With respect to the Trinity Doctrine, none of the popular illustrations are completely accurate descriptions. The egg fails in that the shell, white and yoke are parts of the egg, not the egg in themselves. The Father, Son and Holy Spirit are not parts of God, each of them is God. The water illustration is somewhat better, but still fails to adequately describe the Trinity. Liquid, vapor and ice are forms of water. The Father, Son and Holy Spirit are not forms of God, each of them is God. So, while these illustrations may give us a picture of the Trinity, the picture is not entirely accurate or complete. An infinite God cannot be fully described by a finite illustration.
Instead of focusing on the Trinity, try to focus on the fact of God's greatness and infinitely higher nature than our own. "Oh, the depth of the riches both of the wisdom and knowledge of God! How unsearchable are His judgments and His ways past finding out! For who has known the mind of the Lord? Or who has become His counselor?" (Romans 11:33-34)
Jehovah God is God the Father, God the Son, and God the Holy Spirit -- three Persons, one God. Tertullian (160-215 AD) explained, "We define that there are two, the Father and the Son, and three with the Holy Spirit, and this number is made by the pattern of salvation... They are three, not in dignity, but in degree, not in substance but in form, not in power but in kind. They are of one substance and power, because there is one God from whom these degrees, forms and kinds devolve in the name of Father, Son and Holy Spirit." (Adv. Prax. 23; PL 2.156-7).
God is Beyond Comprehension!
The core of the Trinity Doctrine is the reality of a triune Godhead - God lives in fellowship and relationship with Himself. This is a difficult concept to grasp. But let's put a God-sized doctrine into perspective -- God is beyond our comprehension. "'For My thoughts are not your thoughts, nor are your ways My ways,' says the LORD. 'For as the heavens are higher than the earth, so are My ways higher than your ways, and My thoughts than your thoughts'" (Isaiah 55:8-9). It shouldn't bother us that we can't understand "tri-unity." We can't comprehend infinity, eternity or electricity either, but reality is real whether we can comprehend it or not.
All we really need to know about the Trinity Doctrine: "Go therefore and make disciples of all the nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit…" (Matthew 28:19)
