Sounds like your son had parasites, the tan roundworms are very skinny and around 1 to 2 inches. These are the ones that web together like a spider web. There will be so many of them you can't begin to count them. If it were my son I would get him to parasite cleanse to kill any eggs that had been laid.
My sister, husband, daughter have seen these type of parasites also. We had a young mother die recently, the doctors said she died of a strange webbing in her lungs, they had no idea what it was!!! Makes me wonder........
If your worm was whitish is sounds like an ascaris, if it was tanish it is a roundworm. Ascaris are the hardest to get rid of.