Tony, I agree with you and I also do not agree with his suggestion that carbon dioxide is responsible.
Sodium bicarbonate is an alkaline buffer and in order for it to produce carbon dioxide, it has to neutralize acid. It is well established that cancer only thrives in an acid environment. Neutralizing the acid kills the cancer.
The CO2 that is produced may be helpful in some respects, but it is the alkalinity that is effective in defeating cancer.