baby choking help???

So
I have a 6 month old little boy called Jacob. He choked on a burp which brought up some milk when he was about 4 months old and he stopped breathing and went red then blue. We ended up in an ambulance and when he got checked out by the doctor, they told us it was acid reflux and gave him ranitidine and gaviscon. Since then, he has stopped throwing up milk but he has choked another 12 times. Sometimes even when he's just sat in his baby chair doing nothing. He has started to wean and will choke on anything slightly chunky. It's sooo scary and my parter and are are so worried. He go to a baby swim class every Sunday and he even chokes if water touches his face, to the point where the teacher of the class comes to us separately and does different "moves" with us. Has anyone else experienced this and if so have you found anything that helps? I know he'll eventually grow out of this when he's older but I need something for in the meantime 😔