your friend is wrong u can get manaphy in PR, but won't hatch until it's in D or P.
1.beat the game
2.Go 2 the Ranger Net
3.Hold R, X, and Left on the D-pad
5.Enter this code: P8M2-9D7F-43H7
6.Play the Mission 'Rescue the Precious Egg'
7.Use 2 DS'(D or P in 1, PR in the other)