Does this mean I'm going to lose my grandpa soon?

My maternal grandpa is 81 and his memory has been declining for some time this year.

I (30 F) was visiting my parents. Mom was doing some errands and dad was watching a war movie. Grandpa overreacted and started accusing my dad (his SIL) of cheating on my mom. I kept telling him, it's me, your only female grandchild and the oldest. He has 3 other grandchildren and 1 great-grandchild; all of them males.

He really thought I was a young, mistress my dad was cheating with. It took a while for him to recognize me. Does this mean I'll lose him soon? I hurts so much seeing him like that.

Updates
8 mo
That's the first time he had an episode of not recognizing me. He's forgetting things but I never thought it would go that extreme of confusing me for a mistress.
Does this mean I'm going to lose my grandpa soon?
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