Greetings in that Divine and Most Precious Name of Our Lord and Savior Jesus Christ!
The father who wrote that seems to be grappling with the two conflicting streams of Christian thought, scholasticism and mysticism. The Latins loved their scholarly approach, and the Orthodox loved their mystical approach, and the peak of these schools was respectively Thomas Aquinas and Gregory Palamas. Unfortunately, from the Oriental perspective in the middle, both schools seemed to go on some extremes. The Mystics got a bit too mystical, and the scholastics got a bit too scholarly, and their theology got a bit harder to understand as it increased in sophistication. This father who wrote the OP article seems to be trying to inadvertantly bridge the gap by his choice of phrasing and terms. The father seems to be arguing that while Christ possesses the fullness of the knowledge of God, this didn't prevent Him from suffering. That is to say, the father is asserting that human beings seem to seek solace in the omniscience of God, like the old adage that everything leads to good in long-run of a Christian life. That God shouldn't grieve because He knows the end of the score, well that is agreeably nonsensical. Of course God can see the end result and yet still feel sorrow because of the current situation, just as if any of us know the long run is good, but the short term is painful, will experience both the bliss of assurance and yet the tinge and sting of pain from the present moment.
I don't think his conclusions that Christ experienced sorrow rather than fear is foreign to Orthodox theology, its just the way he explained it is a bit clumsy. To be sure, there are plenty of points made which can be argued against from an Orthodox perspective, but aside from the devil in the details, the overall conclusion seems sound to me, again, that Christ being the Omniscient Word of God could not experience pure human fear (i.e., from a lack of knowing an anticipated outcome) and instead experienced sorrow (i.e., negative feelings attached to a known rather than an unknown). I would say that God could also experience fear, but not of the unknown. I think humans can be afraid entirely of what they know as much as of what they don't know, but then again, I suppose that is just semantics and why the OP website made this distinction between fear and sorrow. Following their reasoning I find their conclusion sound