Even I wouldn't dye my hair, even if a sibling begged/commanded me to do it for their wedding day. You should've put up resistance to that command and now your paying the price for it.:D
But basicly in order to survive a wedding (especially when single) all you gotta do is follow these instructions and you may get out with what's left of your testicles.
#1: Stay near the Alcohol, if you gotta deal with relatives nagging you than it's a good idea to be near something that can settle your nerves and drown them out. Also incase another drunk relative starts a fight you'll be near the perfect Bar-Fighting Weapons.
#2: Stay the ####### away from the bride and groom at ALL times if possible, if forced to say something to them, smile and give them a gentle lie.
#3: Avoid your Parents, they'll be asking when your gonna be next and start planning YOUR wedding without even paying attention to what YOU want.
#4: Bring a book or Portable Gaming System for when your 'borrowing' the toilet, may save your sanity and keep you away from relatives for awhile as well as the Mother's of unwed women hunting for your testicles.
#5: Smile and lie profusely if cornered by relatives/siblings/parents/guests and mentally pray to God that you get out alive.