Well first of all your friend is a tard and needs to read maybe?
his 5k crit was more like 2 5XX crits overlapping, secondly how are you doing lightning DMG at the end of the video? I thought you only had phis lvl3 in your gear.
As for the knight tanking . . .well maybe he found a way to put more phis prayer stones in his gear then he should be able . . . . . .That or he has a couple of glitched defence rings
My guess is he is stacking more phis resist then he should be able to, EP1/2 phis resist was GODLY because. . .no new skills and no new CC{or in your case, no CC!}