Not gonna lie Denken, your lifting partner's squat needs a lot of work. Focus on these few changes first and then post another check:
1. Initiate with hips and knees together, not knees first, and lean over. Don't try to keep a vertical torso.
2. As you (or someone) pointed out to him: don't go so deep. Stay tight through the descent, and initiate the hip drive with a voluntary movement of driving the hips upwards out of the hole. Don't bounce the hamstrings off calves.
3. Pick a spot on the floor a few feet in front of you, and stare at it. The whole time. The entire way down and up. All 5 reps. Even when it gets hard. Do not look at anything but this spot, so your head position need not ever move.