Walter remained quiet. If he didn't reply then the boy would leave him be. That's how it typically worked, wasn't it?

Assumption looked at the orange, then up to Walter for permission. He considered the offer and shook his head, disappointing the little Pokemon who shook his head in turn to Hungry. Walter didn't want Assumption getting used to generous offers. He knew from experience that food could be a useful motivator in training and teaching. Giving it to Assumption freely would hinder that.