First, let's consider the half-life of Anastrazole. It's about 4-5 days. Which means that after 5 days only 50% of the substance is cleared from your body. He's taking 0.5mg on Friday. By Sunday he's stacking another 0.5mg on top of whatever amount hasn't been eliminated yet. So roughly speaking by Monday there's 0.75mg of Anastrazole in his system (this is not an accurate number, but I hope you get the idea). If you don't allow the medication to clear your system completely, the potential of building up unhealthy levels is quite obvious.
Alcohol was an analogy. Not 1:1 comparison. The logic that he's "taking it now, and feels good" doesn't make any sense to me.
You can drink excessively for years before suffering serious health consequences.
Prolonged use of AI is also dangerous. Although most studies were done on cancer patients, it should be clear that such a strong substance can indeed be toxic.
"Toxicity was reported by 42% of patients, and AI therapy was stopped due to toxicity in 19%. The toxicities reported were similar to those reported elsewhere, except that fewer hot flashes were reported. Osteoporosis was found in a higher proportion of patients on an aromatase inhibitor than has been reported in the literature, but 17% of patients had documented bone loss prior to therapy."
Emerging Data on Side Effects of Aromatase Inhibitors : Oncology Times
If you need more "proof" google Anastrazole toxicity.
Then there's also common sense. You cannot take a powerful pharmaceutical and think that it's only lowering E2, nothing works in isolation. It's like dropping a bomb and expecting it to only kill the bad guys. That's just not how it works.
Why do you think hundreds if not thousands of patients report problems from low dose AI usage? Typically it doesn't happen right away, but please don't be naive to think that an adverse effect cannot happen because it hasn't happened yet.