This was all new to him. Nothing could have possibly prepared him for such a situation. First, his best friend in all of the worlds, who just happens to be a guy, spills his guts to him. He just opened up and let out all the pent up feelings that he had realized over a year ago. Riku had told Sora how guilty he felt for putting him through everything. And despite all that, Sora realized that he too might just feel the same way.