Raz is very good when it comes to learning. (Like, he learns really fast!) But I think it would be funny if he struggled just a little to learn how to control and use his hydrokinesis.
I also like to think Lili would help him as much as she can.
I can imagine her shouting things like: "you can do it!", "Don't stop now, you're almost there!", "Almost! Try again!" And more, trying to cheer him up like those movie coaches with a megaphone.