They must see their lost condition before they ever desire to be saved. Let us review a little grammar lesson. He may, but he can't. It does not lie in any physical defect. It cannot mean man is not able to move his body, or walk with his feet.
Many unregenerate persons pray.
There is no lack of physical power in coming to Christ. The inability does not lie in his mind, or intellect. The unconverted can learn the Bible intellectually just as he can learn math, history, physics, music, etc. Yes, he can believe the Bible is true. There are many true books which have been written by unconverted people.