A.J.
Yikes! Don't let him teach you to come in every 1-2 hours! He's old enough to wake up less/never, and actually not eat at all during the night.
Take it from my step sister and mother of 12. Feed him more during the day, all day long. Not only just a thickened bottle/snack before bed, but add in a few snacks and feedings during thew whole day. Even if he seems fine and not hungry, he WILL take more food. Don't worry about overeating-he won't. If he's truly full, he won't eat. If he eats, he's hungry, even if he seems fine.
I learned this too late for my daughter, she was 1 when I finally mentioned that I was still nursing 2 times per night. My step sister taught me this trick, and she started sleeping through the night 3 nights later. My step sister's kids ALL slept thru bu 2-3 months with this method. My son has slept through the night since 3 months like this and he's a monster eater...I feed him all day.
He's now 18 months, and my mother in law recently visited, took over, and refused to feed him "so much". Sure enough, after three days, he started waking up 2 hours earlier and during the night.
Both my kids are thin and healthy. FEED HIM MORE!
After a few days, when his body registers the new higher calorie intake and fullness, he'll sleep much longer, probably all night.
After you are certain he has been eating more for a while and is totally stuffed, if he still wakes, let him sooth himself back to sleep. Don't go in! He will break the habit of having you come to sooth/feed him at night.