My dad was in the European Theater, but they had already told him his unit was going to the Far East when Truman dropped the bomb.
On the other hand, my father in law was on Iwo and his orders had been cut for the invasion of the mainland. He was Signal Corps, and he'd already had his jeep blown up on Iwo (wasn't even scratched though).
So neither of us or our siblings would be here at all, but for Truman!
GOD bless them all!
LLS
Similar here. My grandfather was a Marine trained as a forward artillery spotter. He would have been in on of the first waves ashore and my mother probably would not have been born.