Is this sentence correct Is the Grammys on?

Yes. That is a correct sentence, or at least a correctly formed sentence*. But there is no content that can be judged as right or wrong.(*It is an interrogative sentence, one that asks a question.)

The correct form is, "Where are you?"

this answer is correct.

"You and him" is correct in a sentence such as, "I sent the tickets to you and him," versus a sentence such as, "You and he should send the tickets to me."

If you use 'you and he' as the subject of the sentence, it is correct:You and he will meet when we get to the restaurant.