I agree with this and can give some personal experience (albeit not COVID related). The summer before COVID hit, my mother-in-law fell and hit her head. That started a 60+ day hospital stay that included brain bleeding, strokes, sepsis, gall bladder surgery, and open heart surgery. There were many days when my wife's mother had no clue who anybody was or what was going on. Needless to say, my wife spent almost every day in the hospital with her mother trying to help out in any way possible and helping to advocate for her mother.
This meant that I needed to not only be there emotionally for my wife, but to pick up the slack and do the various things that she would do while also doing everything I do. I would pick up our boys from school, drop our oldest off at his summer job, take my boys into my office so I could do work while they waited, etc. I even had to channel my wife when my oldest son had an unsafe situation at work. I'm not usually good with confrontations. That's my wife's department, but she was unavailable so I had to step up. At one point, leaving the hospital, I got into a car accident with my boys in the car. It wasn't bad (truck didn't stop quickly enough and rammed into me at a stop light), but again I needed to deal with it alone because my wife couldn't get away from her mother and get to us quickly enough.
The whole situation was stressful for everyone for a multitude of reasons. 60+ days was bad enough. Now imagine if this was for a few years or for life (since we don't know how long Long COVID lasts). Imagine needing to do everything because your partner can't go from the bed to the couch without needing to catch their breath. Imagine your partner having to do everything because you can't seem to hold onto a thought. In fact, imagine just trying to hold down a job with these issues. I can speak from my 60+ day experience and say that stress levels would be through the roof and you'd feel emotionally drained the entire time. You do NOT want to be in that situation!