“Refugee” follows Mike Siv, a Cambodian-American in his 20s, as he returns to his homeland with two friends to get to know the father and brother he barely knows, more than two decades after fleeing with his mother during the Khmer Rouge terror. Siv, who also coedited, narrates the video diary with an engaging combination of honesty and empathy. He's a one-time student of its director, Spencer Nakasako, an Emmy winner for “A.k.a. Don Bonus,” which aired on PBS's “P.O.V.” in 1996 and is also about a young Cambodian-American's return to his homeland.