The reason to take body temp, weight and heart rate:

is NOT to establish progress but rather to diagnose signs of overwork/underrecovery. His training program is very demanding on the nervous system and he has a stressful work schedule so the risk of nervous overreaching (short term overtraining) is significant.

An increase in resting heart rate of 3-5BPM sustained over 2 days indicate CNS overload. An increase of 6BPM+ indicate CNS overreaching. A sudden decrease of 3-5BPM might also indicate neural inhibition.

His body temp helps me establish if his metabolism is stable. He wants to gain size, so if his body temp is suddenly elevated by more than 1 degree, and is sustained over a few days, it tells me that his metabolic rate has increased by 10% and thus he needs to increase his calories to keep on growing.

His bodyweight is also used to diagnose overreaching, but metabolic/muscular overreaching not CNS overreaching. If his bodyweight suddenly drops down (which it shouldn't since his caloric intake is above maintenance) it can indicate metabolic overreaching."