Everyone in Hanna Miller’s family knew her father as a giving and generous person. But as his dementia progressed, he couldn’t recall that he’d already ordered something online just a few hours earlier. Gifts, like toys for the grandkids, piled up so quickly he couldn’t easily pay for them.
Watching his decline was heartbreaking. Miller’s father was a biomathematics Ph.D. who spent his career in pharmaceuticals, living abroad but visiting often, always with suitcases full of presents. Whenever his grandchildren called to ask what he was doing, he would answer, “Sitting and waiting for you.”
But as the dementia worsened, his online shopping habits became more than an annoyance — he would repeatedly order food, and the expenses began to outweigh his modest Social Security and pension income, which covered only rent and basic living expenses.
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Miller knew she had to intervene, but wasn’t sure how. Her sister had power of attorney as her father’s caregiver, so they worked together to cancel his online orders and replace his credit cards with a debit card. This not only upset him and led to repeated conflicts, but forced Miller to grapple with ethical questions about parenting her own father so strictly. She felt she was invading his privacy and stripping away his independence.
“I was constantly second-guessing myself, thinking: ‘Do I really have the right to decide this for him?'” Miller said.
Miller wondered whether AI could help find a middle ground: a way for her father to keep shopping without letting each purchase become a financial crisis. She’d played with ChatGPT for personal use but didn’t feel confident enough to build a real product that would prevent unnecessary orders.
So Miller teamed up with her friend Nikki Elbaz, who had a more technical background. Together, they built a service to redirect users to a fake checkout page at any online store, preventing them from completing a real transaction. They called it ShieldCart.
“I told him that there’s this new AI-based app that’s basically a secure checkout. It makes sure that everything’s right and there are no problems,” Miller said.
Hanna Miller
But this well-intentioned deception went a step further than canceling sporadic online orders, and Miller was deeply conflicted about moving forward.
So she went to her rabbi for guidance. He was supportive, likening the act to performing life-saving surgery on an unconscious patient.
Miller describes ShieldCart as the dignified solution to a very demeaning problem.
“Even though I had to step in and become the ‘parent,’ I was able to do it in a way that he couldn’t feel it,” she said. “He didn’t need me stepping in and saying, ‘I’m taking over. You can no longer be the parent. I have to be the parent.’ He didn’t have to deal with that.”
Miller estimates that the family saved thousands of dollars over a year, while letting her father believe he was purchasing all the gifts and goods he wanted to, and avoiding the bitter fights they’d faced previously.
“It was beautiful to see that he could be generous again,” Elbaz said. “We’ve given him that freedom back.”
ShieldCart was built with Claude Code. It works as a Chrome extension installed on the aging parent’s computer and as a desktop app for the caregiver to monitor their purchases.
The caregiver can block certain websites — in Miller’s case, crypto sites — much like parental controls. The app doesn’t collect real credit card information; it only asks for the last four digits of the card to create more realistic confirmation pages. Different modes allow purchases to be blocked completely, paused temporarily, or processed and reviewed afterward.
In opening the app to outside users — currently in beta testing by application only — Miller and Elbaz are clear-eyed about the ethical quandaries their product engenders. They encourage users to speak with an elder law attorney or to secure power of attorney before installing software on their loved one’s device.
Miller said the app probably wouldn’t work for every family. If children are not as close to their parents, or if loved ones have a less advanced form of dementia, the app may not work as effectively.
Miller’s father died last month. His death came as a shock, as he had been in decent health and still had his wits to him. After a period of mourning, Miller decided to carry on with the app, now working to get it out to as many families as possible.
The goal now, Elbaz said, is to partner with organizations that help people caring for loved ones with dementia. They’ve been gearing up to get more users into beta testing, making the app free for the rest of the year. They’re also developing mobile capabilities for loved ones who only use phones or tablets.
“Knowing that the system we built for him will now help other families navigate these challenges with that same respect and love feels like a true privilege and like a secondary, meaningful legacy beyond what lives on through our nuclear family,” Miller said.
