Steve's mom has a lot to take in after learning of Steve's condition with the metronome. She is played by Laura Innes.

Warehouse 13 Season 4 Episode 8 Quotes

Artie: Alright. Then what is it? What's the evil?
Mrs. Frederic: Have you considered the man that keeps bringing artifacts back into the world? The one who's trying to kill the people you care about? That, this Brother Adrian, is the evil.

Arthur is very busy. You're grown agents, handle it!

Mrs. Frederic