I put in the effort, dear condescending fellow. I cannot find any independent confirmation that these kittens are not drugged or dead- only quotes of Mr. Frees' own claims.
The desire for profit is a powerful motivator to lie when money is to be made and the fact that a person was never caught lying is not absolute proof of their honesty. If he was posing dead or drugged kittens then the public knowing that would hurt sales of his photos, so of course he would be very careful to keep such information under wraps.
I have no convincing proof either way, and as I said I hope he is telling the truth. You are apparently more optimistic than I am and that is valid for you, but I am inclined to have my doubts. My admittedly subjective impression on seeing these photos is that the eyes of the animals look dead. If it makes you happier to give Mr. Frees the benefit of the doubt and believe that these animals were alive and well by all means feel free do so. I remain skeptical in this matter.