I had two colleagues like this in a previous job.
We all theoretically worked 24/7/365 variable shifts (including four sleep-in-on calls each per month- making 20 hours at work, with 8 hours full on, six when we could sleep if there were no emergencies but on site, then another 6 hour early shift) in a small team.
Two team members decided that they couldn't do the sleep in on call shifts, nor any weekend shifts, due to their mental health.
Of the six people left taking the slack one was a carer for her sister with terminal cancer who lived with her, one was over 60 and struggling with her physical health especially circulatory issues, I was the only one juggling the job with school aged children over the first hard lockdown when my dyslexic youngest especially needed significant support - the other three also doubtless had their struggles but we were all told (by our manager- the only person able to work from home, whom we didn't see except on a zoom screen for six solid months, and who spent every zoom meeting telling us how stressed he was by the pandemic) to "pull together and support" the two who felt it would be better for their mental health if they only worked Monday to Friday daytime shifts...
Nobody acknowledged the burden of extra antisocial hours shifts and time away from our other responsibilities this put on the rest of us.
I left, my oldest colleague said to everyone regularly that she'd leave if she wasn't so close to retirement, and another colleague was signed off sick for six weeks just after I left.
We all liked our colleagues but they had absolute blinkers about the hypocrisy of driving the rest of the small, close team to breaking point.