"Well, I am currently a vagrant and it is indeed raining lava and ice. You can go outside to check if you wish. Also, we were invaded by a very ill-considered empire and bombarded for a bit. That may be of interest as well."
She calms down a little bit, but is still very tense, as far as you can see. With a heightened tone she asks,
"So it wasn't a dream then? The Theyins... they're here?" You confirm that this is true and she deflates a bit.
"But... the nightmares... are you saying that those gods are real? She picks herself up with a great deal of struggle and stumbles over to the front door, opening it and staring outside at the battle going on between the two wielders of ice and fire. Said battle is also dying down at this point, as it seems that the attacker with lava and fire is being beaten by the ice kid.
"So the nightmares were right," she exclaims with disbelief.
"This is all real. Those monsters were real. But if this was truly real, then..." she hurries over to her younger daughter and grabs her by the hands, holding her close. She also speaks to the boy at the same time.
"Selene, Artemis, listen. I want you to stay inside. Mommy is going to talk with this nice man outside for a little bit, okay?" The boy, who you assume to be named Artemis, nods quickly.
"And don't listen to the voices. Just keep your mind clear, please. I love you." She gives both of them a kiss on the forehead and leads you through the back door screen.
"I cannot thank you enough for helping me and my children. Is there anything you need right now?"