Who is Tariq from A Thousand Splendid Suns and what is their importance?

Tariq is the one-legged son of a carpenter and Laila's best friend. He loses Laila when she is injured in the rocket attack that kills her parents. When he retuns to Kabul years later, Tariq find that she has had two children with Rasheed. After Miriam kills Rasheed, Laila and Tariq flee to Pakistan, but ultimately return to Kabul and start an orphanage there.