I kind of wonder if Tony even knows that ANYONE from Earth survived. Like, he knows Nebula is alive, but everyone from Earth was wiped away. He doesn't know it was half the people, does he? Only Gamora knows that, I think?

The Avengers on earth know that some people survived because at least Steve, Nat, Thor, Bruce are still around...but to Tony, the only reason he is alive is because Strange traded the Infinity Stone for him. I think Tony doesn't know there's anyone alive on Earth at that point.... Yikes.