I get very--oh, I don't know, fatalistic? zen? calvinistic? There's atemr, I just don't know what it is--about stuff like this.
It happens to me a lot. I'm in a field in which everybody who works for me could probably have my job and do it as well as I do. Every time I'm up for a job, I can name you at least 5 people who should be applying for it, too.
Here's how I look at it.
"It was meant to be. If that's 'my' job, I'll get it. If I don't get it, it wasn't 'my' job; there's something about it that makes it 'not meant for me.' "
And just because I'm out of work doesn't mean I deserve to get a job over someone else. The employer has an obligation to everyone who works there to get the right person. That might not be me.
Even if your brother's experience and work history give him a significant edge, there are plenty of other things that might make the company choose his friend.
The only thing that your brother *does* need to do is to not rub anybody's noses in it. Basically, I don't think he should discuss that job, or the job hunt, in any way other than the most surface of approaches--"best of luck to you," "yeah, I got that job, Tom told me you'd applied to, tough luck for you." (sympathetic--NOT sarcastic tone there--it WAS unfortunate for him, when he didn't get that job. So be sympathetic in a not-too-dramatic way)