My DD is 7 1/2 months and we still have to give her infacol! She just holds onto her wind, so yes I would give your lo some infacol. Another thing, does he seem constipated at all, as this would cause a lot of wind. Most feed thickeners should not fill the baby up, thickeners such as simply thick, or carabel. We thicken with carabel. If thickening with rice cereal, yes the baby may be full quicker as its a solid food you are putting in.
Next thing, is your lo eating a large amount of solids? That could cause the milk refusal. My DD has very little milk and large amounts of solids purely because she will NOT feed more than 2oz from a bottle, she hates the bottle, as had bad experiences with it due to reflux
Do you think your lo has reflux at all? Does he seem uncomfortable feeding. I was going to say going up a teat size in case he is frustrated with the slower flow, but I suspect if it is wind, this may only make things worse. We also use Dr Browns bottles and Gripe water.
My HV said that most babies should have no wind problems at 6 months onwards, but a small amount may just have windy tummys.
How many ozs of milk a day would you say he is getting? Anything around the 20oz mark upwards is good if on 3 meals a day, and you could also offer yoghurts/cheese to increase the calcium intake while you figure out whats going on.
If the bottle is making him windy, he will not want to feed as it hurts, we had to thicken as when DD was feeding you could "hear" it hitting her tummy and refluxing.
I know this is a little muddled but typing as I think
Hope this helps you a little. Any Q's post back xx