Well, that’s a two-layered question, really. One, is he in love with her now? And, two, was he ever in love with her in the first place? And, personally, I think this is one situation where the nature of two characters’ relationship is well and truly ambiguous, fully and completely open to interpretation.
Was he in love with her in KH1? Or was the love we saw really just some form of…obsession or possessiveness? And did he care about Kairi for Kairi, or had she become just one more way for him to compete with Sora?
Or, heck, let’s throw KH1 out the window for a second. What about their childhood? What about before Riku became so dark and so…singularly focused on certain less savory things. What was their relationship like then? What did they mean to each other, growing up?
And what do they mean to each other now? Did Riku “let her go,” so to speak, because he moved on from whatever romantic feelings he may have had, because he realized that his feelings were never genuinely romantic to begin with, or because he simply came to acknowledge that she loved Sora and that the respectful, caring thing to do was step out of the way? These are all big questions, and I don’t think there are necessarily any wrong answers. I think canon gives us enough to work with in all directions, enough for there to be several good, solid, well-substantiated interpretations.
It might be worth noting, whatever your interpretation happens to be, that despite interacting with her very little throughout the rest of the game, his death quote in Kingdom Hearts II is groaning, “Kairi…”