Sam had told her they could keep each other from going batshit crazy. It took one to know one, apparently. They knew what each other were going through. That appealed to Molly since nobody else seemed to understand.
Fortunately, Dean switched the focus of the subject. "I ran out of juice after fighting that thing off out of Thomas' dream. Or maybe it was Harry's." She grimaced then shrugged. "Whichever. I was too exhausted to get back to my head. If I didn't hitch a ride in Sam's head I'd have never made it back. No consciousness equals body in coma, and putting it into a hospital wouldn't have worked since it would have just kept shorting out life support so...dead."