I too use and have used Ilford films both MF and LF and have never had a problem. Since I'm not into the chemistry details, I would add to your recommendations that he mix fresh chemicals with distilled water, expose a roll of film of a plain subject such as a gray card and follow the mfg's directions as to time temperature and agitation. The scans seem to show the defects in the blank areas which I doubt has any meaning but since he wants to correct the problem I think controlling the whole process without injecting variables would be the way to go. I the defects don't show up then he would know that it was something to do with his handling of the process or perhaps something damaged the film prior to processing. Then again there's Murphy's Law.