How long ago did he “get over” his infection?
NAC in normal doses can help loosen up phlegm to expel it. However, if he is continually having issues, look into the “long haulers” FLCCC protocol:
You have access to do much of that protocol all on your own.
We had this bout back in Jan. He was ill roughly four weeks - had a bad complication due to the severity of his cough also.
While his cough is very slowly improving, it is still an issue for him.
I’ll have him look over those links - thank you!