In Country (1989)

Samantha Hughes, a teenaged Kentucky girl, never knew her father, who died in Vietnam before her birth. Samantha lives with her uncle Emmett, who also served in Vietnam. Emmett hangs around with Tom, Earl, and Pete, three other Vietnam vets who, like Emmett, all have problems of one kind or another that relate to their war experiences. Samantha becomes obsessed with finding out about her father.