His ice doesn’t have the area of effect to cover even half the Kaiju.
For an idea, think a giant that towers over even Bertrand’s giant bug form that Cole needed assistance in taking out who’s surging with electricity (5 times hotter than the sun) that Cole’s ice needs to be able to freeze.
It’s not clearly shown in the video I posted by Misaka’s Iron Sand Kaiju once it’s sufficiently charged up disentegrated the golems arm on contact with the amount of heat and friction it was generating
Not only that, but even if Cole can manage to freeze the Iron Sand Kaiju, Misaka can take advantage of the freezing temperatures to make her electricity more conductive which she has done