Does it care (don't like to use the word matter in any context other than mass)whether the light is falling into or attempting to escape from the cener of gravity??
Freeze an instant of time and look at light escaping from a star, or falling toward its center of gravity, let's assume not knowing which way. Take for instance a spot twenty miles away.
The light escaping will be fighting the tendency of gravity to pull it back (consistent with CIG, light [photons] have mass until they reach full "c" speed - they lose their mass along the way. In this manner, they are affected by gravity). As it moves farther away from the star's center of gravity, it will travel faster. And as it travels faster, it loses mass, only becoming a massless photon at the speed of light. [partial loss of matter = Dark matter, full loss of matter = Dark Energy]
The light falling will be slowing, since it cannot both acclerate toward the center of gravity and at the same time accelerate away from it. It slows because it no longer travels at or near "c" rate. It is on its way back to becoming a matter particle.[Similarly, when it hits the screen in the double slit, light stops]
But, lets assume that the profesor is correct and that it is accelerating as it falls. Does it not stop at some point? If not, it must accelerate forever. If it stops, has it not slowed? If it cannot reach escape velocity as in a black hole, it has become the singularity.
Still think light slows as it falls toward a massive object. It attempts to reach equilibrium with that object, which itself is slow. As it does so, it loses some of its manifested spatial character, and reinvents itself as a massive object. As a massive object, it travels slower than "c" (or smaller percentages thereof), even when accelerating toward the center of gravity.
doug (www.cigtheory.com) - website needs work/paper has issues