Have you tried multiple different nipples? He may just not like the nipple, there are a bunch that are supposed to mimic a real nipple, if you haven't tried those yet I would, and just keep offering it, the more you offer it the more likely he is to take to it. My little girl has always taken to a bottle so I'm not much help! :(
Try different types of nipples and different people. The key is to be persistent but while keeping it a positive experience for baby. You want whomever is trying to feed the bottle to be as calm as possible because babies pick up on any stress or tension. Try holding baby in different positions, cuddled with a blanket, without a blanket. I've worked in childcare for many years caring for young infants and have had a dozen or so who refused to drink from a bottle when they started and after some work they all eventually take a bottle.
My second child did not take to bottles when I went back to work. However, she didn't have much of a choice... she got it figured out and eventually did just fine. I agree with the other posts about trying different bottles - we had to do that with baby number 1. With baby number three my husband ( who is a stay at home dad) has had to alter the angle which she takes the bottle to more closely mimic the angle she nurses at. When all of my kids have been young and first starting with bottles, they never got one from me, I think that made a difference too. Keep with it and eventually the baby'll get it figured out! It might not be fun - but - he doesn't have much of a choice b/c you'll be at work. Best of luck.