When my father had a stroke, it was two years before he was even a shadow of himself. Then he passed away a year later. He lost most ability to function, and it changed his personality almost completely. He went from a goofy guy to suicidal and antagonistic. He insulted everyone around him and never remembered it. He had gaps in his memory that were astonishing. I was eight months pregnant, and when he saw me two weeks later, he gave me a weird look and goes "How long have you been pregnant?" and I said "Dad, I'm due next month." and he goes "Oh."
She could have, I hate to say it, forgotten about us. Watch videos on stroke victims and how a stroke affects the memory. Years can be lost, people can be erased. Things have to be re-learned just for basic functions.