The Father and Son are and always will be two separate beings. In John's
vision in Revelation 4 , he saw the Father sitting on the throne, not the Son. Notice how Rev 5 is a continuous account of Revelation 4. In Rev 5:7, John witnesses the Father handing the scroll to the Son (lamb). John saw both the Father and the Son.
That contradicts 1 John 4:12 right?
"No one has seen God at any time. If we love one another, God abides in us, and His love has been perfected in us"
And it also contradicts the words of Jesus in John 6:46:
(Not that anyone has ever seen the Father; only I, who was sent from God, have seen Him.)
A vision is not equivalent to the actual experience. Ever had a dream that felt like the real thing? A vision can seem real to the one who sees it, but it is still a vision. Remember when Christ was transfigured before Peter, James and John? Mat 17:1-9 in v9 Christ told them
"Tell the vision to no one until the Son of Man is risen from the dead." Look how real this vision was to Peter:
(Mat 17:4) "Then Peter answered and said to Jesus, "Lord, it is good for us to be here; if You wish, let us make here three tabernacles: one for You, one for Moses, and one for Elijah."
Notice how Paul described his vision of the third heaven, the place of God's Throne.
2Co 12:2-4 I was caught up to the third heaven fourteen years ago. Whether I was in my body or out of my body, I don't know—only God knows. 3 Yes, only God knows whether I was in my body or outside my body. But I do know 4 that I was caught up to paradise and heard things so astounding that they cannot be expressed in words, things no human is allowed to tell. NLT
So Peter, James, John and Paul all saw something of God's glory but it was only in vision, Although it seemed and felt quite real to them.