I just had a flashback of this from my brief stint working at McDonalds as a teenager. I was going through some very difficult times with my mental health, and was on disability for these issues. (They were aware of this).
I broke down at work one day and said I think I needed to go home. My assistant manager (who nobody liked) proceeded to tell me that she came into work every single day while undergoing chemotherapy, and because of this I had no excuse to go home. I felt so upset and misunderstood at the time. I ended up quitting shortly afterwards.
Looking back, I kind of feel sorry for her. I wonder if she still works as a McDonalds assistant manager, passing on her “wisdom” of never taking needed time off for one's health.