I'm so sorry that you had a medical trauma, and are dealing with severe brain fog.
Have any of the doctors (particularly the neurologist) offered any reasons(s) for the condition?

I don't experience it all the time, but when I do, it is indeed difficult to deal with. Definitely can't focus, can't concentrate, and comprehension is also affected. Makes me feel frustrated, tired, and even upset. I can read a short paragraph and then have to re-read it because I just can't seem to answer my question of "So what does this material even mean?" Same with directions on a recipe, even one that I've used before. I've taken to typing recipe instructions in large print (font size 14 of Baskerville or Avenir), and break down the steps, so they show one per step. (Print outs are then placed into page protectors and then into a binder.) I reword the directions also, so that it is VERY simply worded, all excess deleted. I have all ingredients listed together as what makes most sense to me (I've been baking for 52 yrs so I'm comfortable changing things around this way). All dry ingredients together (including spices, etc); all liquids together; clearly list the others as needed within the process itself. I also list tools, etc. And I have whatever pans/sheets are needed with each prepped to my specifications (I love lining with parchment slings -- makes everything so less taxing).
Our 16 yr old grandson loves using my recipes. He's an aspiring chef and says that grandma's methods are what he finds makes for best organization for baking/cooking. He breaks down a recipe that he finds in a book/magazine in the same manner.
Anyway, I wanted to explain how I cope with brain fog in the kitchen. I list steps/ingredients, etc the same way for meal prep/cooking. And I do NOT encourage company in my kitchen because I have other issues that make it impossible to have someone chattering and interrupting my already "compromised" and foggy brain😁. I really need to concentrate.

For daily living, I learned to use post it notes a long time ago. Without those reminders, life can be so stressful and full of anxiety (more than I already cope with). I write ALL appointments along with contact info onto my Google Calendar, along with at least 3 "reminders" scheduled to be sent to me, inclusive of one on the very date of the scheduled appointment. Grocery lists: Learn to write down items according to where you'd find them in the store. I put all produce together; meats together; same with dairy and frozen foods. I go into the store prepared to aim straight to those areas only. So less stressful! In and out in almost no time b/c I go when stores are less crowded.
Medications: Buy two pill organizers of different colors. One is for my morning and the other for evening pills/supplements. Plan on re-filling them on a time of the day that you are most alert because I've found that manufacturers have taken to changing the color or shape that I've gotten used to! AAAaagh! These organizers will help keep you on track with meds.
I have other suggestions for what has helped me tremendously. Let me know if you wish to have them.

On days that I most most foggy, I don't even leave the house. I don't do much in the house either, instead taking it easy, a short nap if I need it (I don't sleep well at night), find a chic-flick on TV and indulge myself. My hubby understands and gives me free-clearance, finding stuff to do that he enjoys.

You bring up the issue of depression: Yes, that has been with me just about my entire life. I cannot take antidepressants, but I have not noticed a connection between times that I'm especially depressed and brain fog. Depressive periods affect me differently.

I urge you to have your neurologist explain and guide you regarding your rightful concerns.
Please let me know how that goes.
Receive a virtual hug of compassion and caring from someone who does understand.🤗💖😊