That's a really good story. Boxing may not be the most popular sport around the world but top boxers are always adored in their home countries. It's a sport which always unites people, so hopefully boxing can do some good in Afghanistan.
Traditionally, martial-arts has been more popular in that region. Would be great to see boxing emerge from there. Physically, Afghans are durable people.
As a whole, Afghans are scrawny in build and short in height. They have cracking beards though so that should stand them in good stead.
Lighter divisions, maybe? Even though you're speaking literally about their beards good), I'm pretty sure they could take a good punch. Seen a few Afghans/Pathans in street fights, and they can handle themselves.
Compared to white/black folks, I'd say Afghanis -- much like Pak!stanis -- are shorter/smaller. Not to the level of Chinese people, of course. But if they were to ever venture into boxing, they'd be like the Latinos and operate mostly in the lower weights.
The Afghan kids in London are jokers, they are in another world. Would be good to get them boxing rather then hanging on the streets. Good luck to them on this though, spread the sport far and wide.