@MedjedovicI mean, I know it sounds a bit overpowered, but the idea is that he can basically manipulate water on a sub-molecular level, causing motion in, separating, and combining its component parts (oxygen and hydrogen). Since H2O is a very polar molecule, ripping it apart is likely to make it magnetically unstable. That same polar nature also actually makes water a very mild adhesive. I feel it'd be hard to separate those abilities (or at least the possibility to develop them in the future) from a scientific perspective or explain why he could freeze/evaporate water but then be unable to make it move or why he could create/destroy H2O without the associated consequences.
I'm not looking to have a character who just comes in all guns blazing and pwns everyone with a million OP abilities, but I
am a bit tired of 'water' mages/casters always being the poor step-brother of 'fire' mages/mancers/casters whose only purpose is to be support and an obvious thematic counterpoint to 'fire', and being calm, collected, life-giving types. I'd love to see the fact that water surrounds us far more than fire and is so absolutely essential to how we and the world function explored. I'd definitely be willing to re-examine and clarify things if need be, but I'd like to keep the premise of the character intact if possible.