I don't know the whole situation, but it may be that he's not eating enough during the day. Does he sleep late or takes long naps?
My son, he would sleep late and eat late, especially at night. So, I had to get him on a regular schedule and adjust his diet. For example, start eliminating one to maybe two bottles with meals or fruit cups. When he screams for a bottle, maybe give him some fruit first, then if it doesn't work, then give him a bottle. When he gets hungry at night, give him something light (only if he's had good meals during the day). Gerber graduates fruit puffs (only if he's ready) works great at night along with a fruit cup and some juice or water.
I can't speak for everyone, but I was able to get my son off the bottle by the time he was 1. Just try a few methods and see if it works.
I know that this is repetitive, but you need to start now with weaning him from the bottle.
I hope that this helps!