He is right and wrong.
We do not have free will, and we do have free will.
It is true, that everything is physically explainable, and thus "CAN" be calculated, if all information was correctly imputed and computed. You can predict how a die would roll if you knew all the factors.
Yet, we are not creatures who can receive all this information and we are not creatures who can compute it all. Therefore, no matter how hard we try to predict what will happen, there will always be an area of error. In the area of the highly complex human brain, it is easy to see if someone is thinking, and even to tell if someone is lying, but the information is too complex and massive to actually predict what their free will is.
Even if you can predict what someone will logically do, it's harder to predict someone illogical.
But there are consequences to our actions. So therefore, we must act in forethought to consequence.
You can say someone has no free will, but he still has the logical capacity compute factors, and therefore should face the consequences as a weight of his computation. If he was a criminal who claimed he had no free will, we must still punish him, because it is still a logical consequence.
However, free will or not, you still have a consciousness, which is an observer to reality and you have no way to predict what someone will do, nor predict any other large events. So to your subjective mindset, you and everyone does have free will, because there is no way to calculate will otherwise.