There are a total of 14 apples/box x 3 boxes = <<14*3=42>>42 apples in the 3 boxes.
So, Henry and his brother each have 42 apples / 2 people = <<42/2=21>>21 apples/person to consume.
Since there are 7 days in a week, thus, both of them can consume the 3 boxes of apples in 21 / 7 = 3 weeks.
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