I can tell by the way he talks that he has a degree in physics, so I dont want to sound direspectful....

Snow takes a LOT of energy to melt. Look at the Poles, 6 months of sun and there is still snow there.

If he thinks this is odd behavior and a sign of fake snow, then redo the experiment with real snow and see how it reacts.

or maybe... all snow is fake and the Earth is flat