The OP's proposed translation is not possible because the word, "God" or "deity" is NOT in either the accusative case nor the dative case to make such possible.
Indeed, the only nominative words in the final sentence of John 6:27 are: "Father", "The God" which puts them in apposition. Thus we are compelled to translate this final sentence as something like:
For God the Father has sealed Him [ie, the Son].
or, preserving some of the original word order more:
For Him [the Son], God the Father has sealed
A similar sentiment is found in John 3:33 -
The one having received His testimony has set his seal that God is true.
APPENDIX - More examples of God and Father in apposition:
In John 6:27 we have God and father in the nominative case. Here are more examples:
- 1 Cor 8:6 - 1 Cor 8:6 - nominative case
- Rom 1:7, 1 Cor 1:3, 2 Cor 1:3 - genitive case
- Rom 15:6 - accusative case
- 1 Cor 15:24 - dative case