It is so hard to not cheer the mouse on. Isn't there ANY type of alternative to live food? I love mice! As for advice, I assume that Pythons have pretty good wildlife survival skills and other than a tiny bit of discomfort, I don't think you should worry too much, just make sure your brother knows what happened (I had trouble following, you did tell him, right?) and if he seems to display any odd behavior, or seems to be in pain, just encourage your brother to take him to the vet, or at least give him a call.

P.S. Poor, poor, poor mouse. I know it's the natural order but still....