Hi Kate!
It's a good thing that your son's conditions were discovered and rectified early, and now he's on the road to recovery. If you don't mind sharing, can you please advise how was his TGA discovered?
What is your boy's weight now? Besides requiring antibiotics before he goes for any teeth extraction, does he need to be on long term medication? Information from the link you gave seemed to indicate that a life-long monitoring, and possibly another surgery, is required. I may have interpreted it wrongly, though. The website didn't say anything about the cause of this condition. Tried searching through the web, but couldn't find anything on the cause. Did the doctor mention anything? Or is it like ASD, where the cause is unknown?
It's your good fortune that you have so many people behind you during those tough days. You have also been very strong and persistent in giving your son the best. It's not easy to travel between home and the hospital during confinement, and transporting breastmilk at the same time. By the way, are you still breastfeeding your son?
Your son is a fortunate boy. Things will only get better for him.