What Is Evil About Dungeons And Dragons?

Dungeons & Dragons is a table-top role-playing game which was originally designed by E. Gary.
The players of D&D create characters that embark upon imaginary adventures and the Dungeon Master serves as the game's referee and storyteller. But i think there is no such harm in playing it and it wont make him evil. So relax and give him sometime to change himself slowly.

There is no such thing as an evil game, just evil people. If you blame your behavior  on games or movies or other outside stimuli, your are trying to convince yourself that the evil you have done was someone else's fault. Know the difference between fantasy and reality and enjoy fantasy while you can.
And remember Pat Robertson once said that the Smurfs were evil.

The best description I ever heard of D&D is improv theater without the building.

People hear spells and they panic and jump to conclusions and they don't bother asking .

Spells work this way -
A. You check which spells you have available on your list
B. You tell the GM what you plan on doing on your turn
C. You roll a D20*, rolling high is good, very good.
D. If you roll high enough the spell worked, too low it failed.

I don't know of any group where the gamers play the bad guys. I'm sure there are some. Most of us who play are out to rid the world of bad guys while making a little (okay a lot) of money along the way.
*(D20 a twenty sided dice)