With two succeeding generations of a Mitochondrial Disease diagnosis, there can be no doubt about your diagnosis too. You lived until almost 90 years old, but your last 15 years were in a hospital and many years before that were in-home care.
Rest easy, Mum you have a flock of Mito angels to keep your watchful eyes upon with your endless patience and understanding smile. I am sure they are OK!
I love you.