So you are saying the reason he cannot do it "with ki" is because of his harmful intent or state mind. I am going to assume by ki you mean without effort, softly, blending, or whatever commonly gets interpreted as ki as opposed to the opposite of ki which I think u mean force, strentgh, sped, timing, muscle.
Kind of but not quite.
He is running into something he knows not what. I do get him to relax more and use Ki yes along with anything else that may be out, be it technical, positional, mind etc. But yes the main important one I would be emphasizing is Ki.
Now he may be someone who 'uses Ki' already and thinks he's relaxed. But the same applies for there are many misunderstandings about Ki also. All those misunderstandings are based on wrong intentions and false understandings.
By Ki I mean that energy which is of course spiritual but you could say it is life energy, healing energy.
Opposite to Ki? I try to keep away from using the word opposite but rather get people to recognise what it's not so yes it's not force or muscle or that kind of strength.
As for timing and speed well that does have something to do with Ki as well as other factors.
From harmful intention you may produce an energy but that energy isn't Ki no matter how many 'experts' say it is.