Did Thomas address the Father as ὁ θεός μου in John 20:28?

 A Unitarian said that in John 20:28, Thomas said to Jesus ''my Lord'' and Thomas said to the Father ''My God''.

My response: 

If you have seen him, you have seen the Father.

That is in John 14:9 and it's not even about the physical appearance of Jesus! it's about works based on context (vv. 9-11) [1]. Thus, it has nothing to do with John 20:29 which has Jesus blessing those who believed even if they did not see his resurrected physical body!

If you insist that the Father is seen in Jesus' risen body in John 20:28, then, to be consistent in your logic the Father is seen crucified since Jesus is seen crucified, that the Father is seen dead since Jesus is seen dead and so forth.

John 20:28 explicitly states that Thomas is speaking to Jesus alone as evident by the singular pronoun in the text [2]. 

John 20:28 explicitly states that Thomas is saying ''my God'' to Jesus alone based on grammar.

There is no evidence that the Father is being addressed as ''my God'' in John 20:28. The Unitarian's alleged contextual argument from John 14:9-10 is an example of eisegesis (the interpretation of a text (as of the Bible) by reading into it one's own ideas). 

Notes

[1] Seeing the actions/works of Jesus is equal to seeing the Father. In this case, the Father is seen in the works, not in the literal appearance of Jesus. 

If Jesus were working, and Scripture says that the Father himself, dwelling inside Jesus, is working in Jesus, it means that Jesus is not performing his miracles alone. Jesus did perform the miracles but the Father also performs them ''inside Jesus'' (''The Father is in me...'' John 14:11b). In the same verse, Jesus also performs his miracles ''inside the Father'' (''...and I in the Father'', John 14:11b). The mutual indwelling of the Father and the Son is explicitly stated in John 14:10-11 and it refers to their works in that they do the exact same thing. This mutual indwelling is not literal (neither the Father literally is inside Jesus nor Jesus is literally inside the Father). 

Do you not believe that I am in the Father and the Father is in me? The words that I say to you I do not speak on my own authority, but the Father who dwells in me does his works. John 14:10

Believe me that I am in the Father and the Father is in me, or else believe on account of the works themselves - John 14:11

But Jesus answered them, “My Father is working until now, and I am working.” - John 5:17

Summary: Seeing Jesus is seeing the Father (meaning, the Father and Jesus doing together the same works). - John 14:9-10

 [2]  John 14:9 says that seeing Jesus is seeing the Father's works in him based on context (vv. 10-11). This is entirely different from saying ''my God'' to Jesus whose literal body is seen in John 20:28-29. Thomas was not addressing the Father inside Jesus in John 20:28. Thomas did not say ''my God'' to the Father in John 20:28. The author explicitly writes the pronoun αὐτῷ which in context explicitly has Jesus (not the Father) as the antecedent.

In John 20:28, based on John 14:9-10, Thomas sees the work of the Father in Jesus (i.e. raising Jesus from the dead) but there is no indication that the Father is being addressed as ''my God'' in the text. Thomas was speaking to Jesus alone in the verse. Based on the grammar of John 20:28, Thomas did not say to the Father ''my God''. Thomas only said ''my God'' to Jesus alone, the only antecedent of the singular pronoun in the same verse. 

Thomas said to Jesus ho kyrios mou (''my Lord''). Thomas did not only say ho kyrios mou to Jesus. Thomas adds: kai ho theos mou ('' and my God''). Based on the grammar, Thomas said to Jesus alone the 2 phrases ho kurios mou (''my Lord'') and ho theos mou (''my God'') conjoined by the conjunction kai (''and''). The text has a singular pronoun auto (''him''). 

There is no evidence that the Father is being addressed as ''my God'' in John 20:28. The Unitarian's alleged contextual argument from John 14:9-10 is an example of eisegesis (the interpretation of a text (as of the Bible) by reading into it one's own ideas).