Alpha dog question?

I'm fostering two brittany/lab mix pups that are about 9 weeks old. I named them Remus and Sirius (yes, I'm a huge Harry Potter geek! LOL) My question is this: Remus is obviously the alpha dog. He rules the roost. He even tries to keep Sirius from eating. Sirius is a huge pansy. He is scared of my cats, plastic bags, his own shadow, etc. How do I help bring Sirius out of his shell and let Remus know he can't boss his brother around like that? Do I try the Cesar Milan trick of making Remus submit to his brother when he keeps Sirius from eating? Any advice is appreciated. Thanks.