It sounds to me that this man is not a very objective scientist to draw this conclusion:
"after reading the Bible, (I) decided that there could only be One True God, and this was the one that created things as complex as the human brain."
He decided on the basis of reading the Bible (which was polytheistic in its early texts) that there must be one god and not myriads. Where does he supply evidence for monotheism? Does it follow that the human brain was created by this one god? Not at all, it is just a belief.
In other words it is merely his opinion since he gives no solid basis for it. For example, the notion that a god exists is the same premise for all believers and yet it has to be agreed there is no concrete evidence for god and equally no evidence that he does not exist. This balance does not make a god more likely. Unless evidence could be found no one should proceed on the basis of belief. If he uses mere belief in his professional life of old age related care he would be dismissed.
It is here where the friction lies and the JW org takes advantage of it; where a scientist gives personal opinions which are sanctioned as acceptable only on the basis of his or her academic status.
Fortunately the scientific world attracts fewer believers these days but those who are can be pounced on for theist quotes.