Not every character gets his history spelled out, on several characters there is still something left uncertain and i.e. Terra's struggle with the darkness was also not always spelled out, but shown in how he reacts, which Sora also does, and more than any other character because he gets the most screentime (aside from Riku).
Sora and Riku had their reconcilement scene at the end of KH 2 on the dark beach and during various scenes in The world that never was before, even partly in CGI.
It was also already covered how Sora felt about it, as he didn't cease to search for Riku and also in his numerous encounters with Repliku (who he thought to be the real Riku) it was quite clearly shown that Sora already forgave Riku.
If one wants to be nitpicky one can even say he already forgave him way before in KH 1 when he realized he was controlled by Ansem SoD.
Sora and Riku had their reconcilement scene at the end of KH 2 on the dark beach and during various scenes in The world that never was before, even partly in CGI.
It was also already covered how Sora felt about it, as he didn't cease to search for Riku and also in his numerous encounters with Repliku (who he thought to be the real Riku) it was quite clearly shown that Sora already forgave Riku.
If one wants to be nitpicky one can even say he already forgave him way before in KH 1 when he realized he was controlled by Ansem SoD.