Prometheus settled both his hands around the one that Thalia was squeezing, trying to offer as much of his strength as he possibly could. He doubted it did very much, but the goal of it all was to offer something.
When Hygeia said his daughter was present his heart skipped several beats and he tried getting a glimpse. He was momentarily panicked when the girl left his sight and felt torn. He wanted to greet his daughter, but his other baby was still coming too.