How would you explain this sentence?
School is closing two weeks for Easter holiday. Then comes the end of the term soon, and summer. Most of the boys will go home, but not all. Some have to stay for remedial maths and repeating Virginia history in the sweat of July. Living here in the sock-stinking dormitory, and not with Father. He clearly explained that, in his letter about coming to visit while school is closed for Easter holiday. That will be swell, he says, a visit with old Dad. Swell enough for two weeks, not the whole summer.
How would you explain the last sentence: Swell enough for two weeks, not the whole summer?
Does it mean the father only wanted to let his son live with him for two weeks not a whole summer?