Little bit of analysis from me:

Unfortunately it is 2am and my brain is too slow to find all the clips I wanted to but let's do a run down:

Kaoru is a watcher through and through

He watches Langa likehis life depends on it

He immediately started taking notice of him, despite how little he really seems to engage or care for other people

He figured out he was a skilled snowboarder extremely fast

Offered Reki a ride on his carla-cycle (?) just to prove this point

He started getting close to the kids (despite making it very obvious how little he cares for them in eps like the beach ep)

And as Kojiro rightfully states. He's just using them. To get to Adam.