First off....it won't work if hubby isn't backing you and helping. So, how do you get hubby on board? Well I used money with my hubby. I figured out how much we were spending on Diapers, Wipes, Baby Rash Cream, etc. Its over $100 per month. What could your family do with that much money each month? Once he gets on board you should have better luck with your son.
I admit that your son might be too little to potty trian for my house. However, with my younger brother my parents had him stand and pee with his 'hose' and try to hit the Cherios in the toilet. He was into firefighters and he found it to be the most fun. I would also reward him for even trying. With my little one we did songs and finger plays and such while she sat on the potty. And when she was on the potty was the only time we did them. She would ask to sing "10 Little Monkies" and I would say "have to sit on the potty while we sing" and off we would go. Consistancy is always the key with children.
H. that helps some, best of luck.