No one was supposed to know about this. Julia shouldn't have told anyone about this big secret and they both agreed not to talk about this anymore.
So much so, there was a point where Tony believed that Emily was not his own daughter. He had always thought of her as someone else's child and he was just there to fill the father's role for her.
It was pretty messed up, but it helped Tony feel less guilty toward Dawn's mother.
"This is not the time for that!" Jason said harshly. He probably wanted to buy some time for himself to come up with a reasonable excuse. "Your daughter is going into labor!"
Jason then dragged Tony out of Dawn's bedroom, while Emily had been taken to a nearby room. From the looks of it, she was going to have early labor.