Hey there, maby try giving him some milk in a sippy cup and then give him the bottle when he gets upset with the sippy cup, keep it up and i think you'll find that he will drink more  and more from the sippy cup before getting sick of it as time goes on! Be patient and persistant and you'll get there! Good luck!!

P.S this kind of thing works with kids of all ages! I used it to help my son play with his toys at 2 months old. I would put him under his hanging toys and every time he touched one of them with his hand, I made a big fuss about it. Within 10 minutes I had him swinging at the thing like a boxing bag!

Make drinking out of a cup fun and exciting, reward him when he does the right thing (taking sips from the cup) make a huge deal about it like clapping your hands and going "yaaaay good boy!" kids are more likely to do the right thing again if they are positively encouraged.