He would be proud that atheists were able to question reality. He would be pleased with the fact that they were skeptical of his existence. He would let atheists into his heavens and would explain himself to them. God would be open minded and willing to tolerate atheists.
God would feel glad that he created people who were daring enough to question things they didn’t understand or lacked enough
proof of, especially the belief in him.
PS: God does not exist.