Is there an HR reddit?

This is gross but it sounds like your employer may be misinterpreting a law that covers discrimination in the workplace against people based on medical or health conditions. You may have to make this issue a hazard to your health and to others vs them worried about talking to your colleague. If there is any interface with customers maybe you could use that too. However, if your workplace is a bit secluded and there is none of these and it just you, try to find somewhere else to work whether it be another section where this person has no access or find a better job. Sometimes jobs can have areas where management seems to not care as long as a certain level of work is accomplished and from what you describe, that may be where you are. It may be difficult to change and often it is better to move on.