Thickening breast milk

Ri

Baby is 4 months old and he is choking and spitting up. He has to be always elevated. He is on acid reflux medicine. He has his tongue tie reversed. He is lipped tied however the pediatric ENT thought he was fine. Doctor now is sending us to a speech pathologist thinking baby is having sensory issues with liquid. He thinks we need to put him on bottle and thicken his milk. Does anyone have experience with this? I am going to be so sad to stop breastfeeding him as it is such a good experience for us. I also want him safe and the choking is terrifying and no is sleeping and even driving with him in his carseat is dangerous.