The 16-year-old shared a heartfelt post on Instagram, accompanied by a short clip of her and her “nanny Ruth” exchanging kisses.
“There's no words that make sense right now,” Brown said. “There's no feeling to pin point.
"Loss is something so complex and I go thru spells where I can’t stop crying and then I laugh about all the memories and then sit quiet and try to comprehend what happened. Alzheimer's is evil. It’s cruel.
“Taking away someone’s ability to remember memories and then how to function like a human being. It’s so hard to sit there and watch,” she added.
Brown, who made her name as Eleven in the hit Netflix series Stranger Things, shared childhood memories of her grandmother and noted the impact of Covid-19 of their lives.
“I couldn’t come home to give u one last snuggle because of Covid-19 so FaceTime was all that we had. I sang to you as much as my voice could take it, even when u were sleeping,” she wrote.
“I loved you more than anyone could ever love. I’ll tell everyone about you and the lessons u taught me. I’ll thank you every day for the laughs and memories u gave me all through out my life so far.”
Brown previously opened up about her grandmother’s battle with dementia and Alzheimer’s on the social media site.
Writing in June 2019, the teenager wrote: “To everyone who is watching their loved one go through this, remind them of all the love they deserve.”
She closed her tribute by describing her grandmother as “my guardian angel”, adding that she hoped “time will somewhat heal”.
“Rest easy nanny,” she finished.
Brown’s Stranger Things co-star Noah Schnapps paid his respects in the comments, writing, “Rest easy nanny.”
And Breaking Bad star Aaron Paul said: “Oh Mills. I'm so sorry. Love to you and your beautiful family.”
Production recently resumed on season four of Stranger Things after a six-month shutdown caused by the COVID-19 pandemic.
The award-winning actor is set to reprise her role in the 1980s sci-fi series, which is not expected to hit screens until at least summer 2021.
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