"And I could never take her place." Della isn't hesitant to say that. As much as she loves her Uncle Scrooge, he couldn't take the actual place of her real parents. "I wouldn't want to. I'm not asking you to replace anyone."

A little smile. "How about 'cool aunt'? Or 'awesome big sis'?" It's said a little playfully, hopefully letting him know things are cool between them. She doesn't HAVE to be everyone's mom - she never could be.