I have an employee with an accommodation that lets them work from home some days, but others on their team are beginning to ask questions. How do I respect the privacy of someone with a disability?

I have an employee with an accommodation that lets them work from home some days, but others on their team are beginning to ask questions. How do I respect the privacy of someone with a disability?

This question pretty much covers it. (fake names) Sally works from home two days a week due to a medical disability, but now Mark is mad he can't work from home and keeps pestering me about it. How do I get Mark to back off, respectfully?