Best of luck with this illness.
Hope you get correctly diagnosed soon.
I sort of doubt that there is enough deoxygenation to cause cell death in the brain, and if that really IS the case, my non-professional advice would be to discuss this with a competent doctor. Cell death can also cause loss of motor skills, and other important skills that are needed for life.
Either way, best of luck with this, I do have a couple immediate family members suffering from severe, incurable diseases, so I sort of know where you are coming from.
Keep fighting the good fight.
Sincerely,
Abdur