My dad was diagnosed with dementia 5 years ago. It's hard watching him slowly slip away.

• My father has vascular dementia caused by strokes, diagnosed five years ago.
• These days he has trouble even operating a phone.

The first time I noticed my dad was suffering from dementia, he asked me to pull through the ATM. I was driving, so he handed me his card and told me his PIN — not that he needed to; it'd been the same since I was a child.

But when I handed him crisp $20s, he looked at the bills with utter confusion, unable to understand what they were worth or where they'd come from. I hid my tears as I tucked the money into his wallet.

At that point in 2017, I was already used to parenting my parent. I grew up knowing my dad was bipolar. A severe mental breakdown when I was in college left him unable to work, and he moved from our family home back in with his mother. For years he rarely got out of bed. Then a series of small strokes set him back even further.

That day in the car, I felt terrified. Mental illness has cognitive effects, and I'd seen my dad dazed or confused before. But I always had hope that his symptoms might abate with the right form of medication and therapy. As a health reporter, I've written about dementia. I knew the condition was progressive, and the reality was that my dad would get worse, not better. The hope I'd held for the future — working on writing projects with my author father or watching him frolic with my children — slipped even further away.

My dad has trouble dialing the phone now

A few short years later, my dad was unable to care for himself. He was admitted to a nursing home with a diagnosis of vascular dementia, a type of dementia caused by changes in blood flow to the brain. In my dad's case, it was caused by strokes. It's different from frontotemporal dementia — the type the actor Bruce Willis was diagnosed with — which can affect personality, but vascular dementia still changed who my dad is and my relationship with him.

There are lots of misconceptions about dementia. Sometimes my dad's long-term memory is better than mine. He'll tell me about dreams he had when I was a child or recall conversations with neighbors we haven't seen in years.

His memory loss shows up in small but impactful ways. He doesn't remember to shower, get a haircut, or take his medications — all reasons he requires full-time care. For years he called me 10 times a day or more, oblivious to the fact that we'd just talked. This year he's been unable to operate a phone on his own; the absence of those calls is a blow I wasn't prepared for.

People respond differently to dementia than to mental illness

I've been helping my dad navigate chronic illnesses since I was 18. And while there are a lot of similarities between his bipolar disorder and his dementia, there are stark differences too.

Healthcare providers and laypeople seem to take his medical needs more seriously now. Though both bipolar disorder and dementia are very serious, there was always an underlying attitude that my dad should "just" treat his mental illness: Just take your meds, just do what you're supposed to, just get up. Now that he has dementia, there's a recognition that his brain simply can't do those things — but that was true long before his strokes and the dementia they caused.

While I've always been outspoken about mental health, other family members are much more comfortable talking about dementia than they were about bipolar disorder. It's easier to explain that a loved one's deficits are because of a condition that people have pity for rather than one that's wrapped in blame and shame.

I talk to my daughters about being compassionate for their papa

My daughters are now 4 and 8. We're having more and more conversations about my dad's condition. My oldest daughter, who has an attitude more like a teenager's every day, gets annoyed if he repeats questions or says something strange.

"You have to be patient," I remind her. "Papa's brain doesn't work right anymore."

That's the truth of the matter — one that's so difficult to accept. Dementia is more than memory loss: It changes a person's personality, communication, and interactions with the world. It's earth-shattering, and yet all we can do is love them and ourselves through it.