Go camping and book it a month in advance. Bring lots of booze Hire strippers and have them come to the camp in role play (camping gear), whereby they pretend to befriend your friends and drunkingly (or play drunkingly) strip for them and hopefully the drunk groom. Take pictures as black mail so he never tells his fiance. Take drugs and cigars too and see if he drunkingly agrees to use them.
Then again, maybe he's that lucky guy that finds the right woman in high school and never looks back (like kwilk).