How does Gene change from summer to winter?

Finny and Gene, though their relationship has become more close, have become different personally, especially Gene. Gene has gone back to his old ways, as a law-abiding, tradition-following student. Although he thinks of himself as a bit of a rebel while Finny is away, one Finny is returned, Gene is completely conventional, with his talk of duty and the war and self-sacrifice. Gene almost sounds like one of the teachers in his patriotic reverie, and Finny gives him hell for it‹Finny knows that Gene slips in to this kind of conventional thinking very easily, and he'll have to fight to get Gene to be a less responsible, more interesting companion.