If the nail is thickened and opaque, I would suspect there is a fungus involved. This is usually one of the first signs and the smell also indicates this. You mentioned that he was seeing a Dr today, did the Dr confirm this? If the infection is under control, you can have you son soak his foot in an alkaline solution (vinegar and water will do) This will bring his PH more to the balance it should be and maybe knock out the fungus. If fungus is involved, antibiotics usually will not kill it, although it will kill the infection the ingrown toenail has caused the surrounding flesh. Once the offending nail is trimmed properly, have your son roll up a minute ball of cotton and insert it under the nail corner. This will relive the pressure and help the nail to grow out in the correct pattern. Again, if fungus is involved, proper washing of stockings and proper disinfection of sneakers must be followed.