That's total bullshit crap!
That's not what Jesus teaches in the Course. Everything He says points to the fact that if your body is exhibiting sickness, it PROVES and demonstrates that the mind is not healed, that you do not fully believe in forgiveness, you are still trying to make the cause wrong (your brother, the world), and are still in a state of attack.
There is no way that you can have perfect peace and have a sick body.
It never made any sense to me how it could be justified or reconciled, that life would be "ok" or "correct" if all the problems in life just kept on happening, but because we're peaceful and beyond it, we just don't care. This is a half-baked state of being which is not ACTING like it really believes that God's truth is true. If you really believe that God's truth is true, you will LIVE IT!
Even if form is an illusion and even if bodies are not real and even if you are not a body, YOU STILL are supposed to be demonstrating God's truth in this world in order to teach others that nothing has happened, that they are innocent, and that you have power over form.
So there is this whole camp of people who are in this mindset, who are "content" to just gain some kind of peace and to then "allow" terrible things to continue to happen, rationalizing that e.g. the world is not real so it doesn't matter, or the peace will not make you want to change anything, or whatever. But if you are in a state of love and power and FULLY BELIEVE that sickness is illusion, YOU WILL REMOVE SICKNESS. Period.
The collective sonship will ultimately, cooperatively, completely DISAPPEAR the entire physical universe, as PROOF that it is not reality, having believed this truth fully.
In many passages Jesus has asked us to demonstrate that the truth that's in our mind is expressed through the body for all to see. And to come up with explanations and mis-quotes as to "why" you wouldn't need or want to do that, is a misunderstanding of the Course's metaphysics, not to mention a misunderstanding of cause and effect. If mind is cause and cause is pure the mind WOULD NOT project a body image of sickness, because sickness is an attack and teaches only that attack is real.