Do you feed your dogs together? If Chloe is an energetic eater that may encourage him to actually eat. In my experience I have found that a little food competition is quite healthy.
Chances are that Chloe will eat his share of the food a few times but Charlie will get the message that if he doesn't eat it she will. To up the ante I would add something really yummy to it like pureed (cooked) liver, chicken or some cottage cheese.
As long as he is not getting too thin or showing signs of illness he'll be fine
Sometimes I think they get a hoot out of testing our patience
