He hadn't told her about Allison, either. He...would. After they figured out what to do about her being on the other side. Either she would remain a ghost, or they would find a way to bring her back. Either way, Chris would tell Elena once he knew for sure what he was dealing with in regards to his daughter.
"Not at all. Isaac's a big boy. He can fend for himself, if he's even there. He might be staying in the dorm tonight."