Hi Paul
Ask the Holy Spirit of God, Who is the Voice of Jesus, Who is GOD to reveal Jesus to Him.

When The Lord Jesus began to draw me to Himself 40 years ago, I heard a "Voice" in my head to call on Jesus as I was praying to GOD.

When I got saved I called on Jesus of course.  I asked Him to forgive me of my sins as I repented.  I asked Him to come inside of my spirit and be Lord and King of my life.

When people tell me they do not believe Jesus is God but believe in God I SHOW them in the bible and have them read out loud or if they cannot read, I read them the following scriptures:

Genesis 1:26
John 14:6
John 1:1
John 1:14
Romans 10:9-13
Acts 4:12
Acts 7:59
Acts 16:29-31 AND
1 John 5:7-8

These scriptures not only tell us Jesus is God but tell us we cannot get to GOD the Father without going through JESUS.

However only The Anointing of the Holy Spirit reveals the TRUTH in our hearts, in our spirit.

May the Holy Spirit bless you with the Presence of God and anoint your words as you share the scriptures with your dad.

Blessings!

Carol Garza