to your nephew:
ask him to explain the striking convergence of species split by 125 of evolution and on entire different branches of the evolutionary tree. Namely placentals and marsupials which look almost exactly the same as one another.
http://txtwriter.com/Backgrounders/Evolution/EVpage14.html
If he can’t explain this you win.
If he explains it correctly he will say that the convergence is parallel evolution of species in similar environments which favor specific gene mutations.
Respond stating that the timeline for a specific mutation to occur in a given species and become accepted with it’s DNA is longer than the life time of a species (Very rare). That him believing that the random events occurred for too many to mention lifeforms to exhibit convergence at roughly the same point in the evolutionary timeline requires blind faith by him in a hypothesis that can not be tested nor proven. Then give him a stern glance and say when he chose to begin this course by stating he would disprove religious myths he opened the dialect to include religious debate. That you choose to believe that there is a guiding force behind the evolution of species while he believes in the option of countless random events occurring to make order out of chaos. Remind him that usually that is not the case, such as in entropy. Then tell him please not to mention religion again or you will be forced to inform his boss of the matter.
125 million years*
It is probably unwise for a student (or anyone else) to bring up entropy unless he really understands entropy.
Those who cite entropy as an argument against evolution are misusing thermodynamics. (I say that as someone who teaches engineering thermodynamics.)