Potty Wars!!!

Let the battles begin!! I'm not very equipped to fight. My mom potty trained the teenager. He went down to visit for two weeks and came back trained. The pre-teen did it on his own. So now I'm fighting a war, that is new to me. I have tried stickers, m&m's, Diego undies, pull ups, two different kinds of potty's and still no luck. The little big boy just doesn't want to go to the potty. I've even tried bribing him with a coke. Yes, I'm starting to get desperate. Here he is sitting on the potty. He kept saying he was going to go potty for an m&m, two hours later still sitting there and nothing. Singing a potty song doesn't work and turning the water on doesn't work. The teenager showing him doesn't work. I'm starting to think this is a game to him and right now I don't have two hours to sit there to see if he will go. Is he trying to hold on to the last baby thing he has? Is it cause the HMIC is not here and he wants no changes? Should I wait till the HMIC gets back. I have no clue! Too bad I can't just send him to potty training classes. So I guess I will keep fighting the potty war and hope it doesn't last long. But by the ways things are looking it will be a long one.