Dad's Apology to Daughter Following Fight Goes Viral 15 Years Later — and Holds More Meaning After His Parkinson's Diagnosis (Exclusive)

"Dear Teann, I'm so sorry about today. I love you more than anything!!! xo Love, Dad. We cool?" the note reads

• Teann Sydney Williams has kept a note her dad, Peter, slipped under her door 15 years ago

• Her father wrote the note when she was around 12 years old after the two had gotten into fight

• Recently, Williams came across the "That Sums Up Who My Dad Is" trend on TikTok. She decided to post about the note on TikTok, and since then, the video has gone viral, amassing almost 900,000 views and 350 comments

Teann Sydney Williams has kept a note her dad, Peter, slipped under her door 15 years ago, and now she’s sharing how that note "perfectly represents" the kind of person he is.

It all began when Williams was around 12 years old and had a fight with her dad after struggling to perfect her tennis serve. She remembers losing a match, getting upset and blaming her lack of progress on him. When the family returned home, her dad went straight to his room.

"I remember saying this so vividly. I was so upset, and obviously, I didn't mean it, but I got so mad I blamed it on my dad. I was like, 'This is all your fault. I hate you. This is why I lost,' " she says.

Although she later apologized to her dad, now 71, she admits to PEOPLE that she still expressed how upset she was — something she now feels embarrassed about. Not long after, she found a note slipped under her door.

"Dear Teann, I'm so sorry about today. I love you more than anything!!! xo Love, Dad. We cool?" the note read.

Growing up, Williams, now 27, was a daddy’s girl. She recalls how her dad never missed a tennis match and was always there for her. When she was just 5 years old, her dad was diagnosed with Parkinson’s disease. Although that didn't stop him from being present, once she hit high school, she noticed his health slowly start to decline, especially after her senior year.

"My dad was someone who never wanted to hurt our feelings and hated seeing us upset. Even more so now, he hates to see us angry or bothered by anything," she says.

"If I was sick, he’d say, 'I’ll call out so you can stay home,' and we’d hang out all day together," she adds. "He’d get me my favorite meal from Souplantation and bring it home. We’d watch movies. He loved when I was sick because we had so much fun doing stuff together."

Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer​​, from celebrity news to compelling human interest stories.

Two years ago, Williams' love for her dad grew as she watched him have a serious fall, which led to a visit to the emergency room to check for any broken bones. Afterward, doctors recommended he go to a rehab facility to help regain some of his mobility. But while in the facility, he contracted COVID-19. He ended up unable to eat or walk and had to get a GI tube.

Since then, Williams says her family has become even closer. "My mom’s his 24/7 caregiver, and my brother, my husband, and I are here to help her," she adds. "We’re all trying to help each other out the best we can — figuring out schedules and what we need to do."

Recently, Williams came across the "That Sums Up Who My Dad Is" trend on TikTok. When she saw it, she instantly thought of the note her dad had written her years ago. "I was like, oh my gosh, that’s perfect. That describes my dad."

She decided to post about the note on TikTok, and since then, the video has gone viral, amassing almost 900,000 views and 350 comments.

But leading up to posting the TikTok, Williams says she had a moment of panic after she went searching for the note, which she had saved. She tore through her box of cards and after realizing it wasn’t there, she recalls thinking, "I’m going to cry if I lost that letter. I love that letter. I don’t want to lose it."

Williams was relieved when she finally found it while cleaning out her car. She had forgotten she left it there after her brother got a tattoo — a tulip, the symbol for Parkinson’s disease. At the bottom of the tattoo, it says "Love, Dad" in their dad's handwriting, taken directly from that note.

"Honestly, there were two sides to it. It was really heartwarming to see people who have had the same experience with their dad," she says reflecting on the comments. "There were people who were like, 'Oh my gosh, my dad would do something like this.' Or 'My dad used to write notes like this to me too.' My dad always apologized. And I was like, oh my gosh, I love that."

"But then it also made me really sad," she continues. "A lot of people commented, 'I've never experienced something like this,' or 'All my 30 years of life, my parents have never apologized for anything.' That makes me sad. I wish everyone could experience what I have. I’m super blessed with the parents I have. I grew up in a really great home, and I’m forever thankful for that. It makes me sad that others don’t have the same."

Since posting the TikTok, Williams has shared it with her dad. "I said, 'Dad, you know what TikTok is, right?' and he was like, 'Yes.' I told him about this trend, and while he’s older and doesn’t fully get it, I tried to explain."

"Then I mentioned that the video got 194,000 likes, and I could see his reaction change," she continues. "He went from not really understanding to being like, 'Oh, that’s so funny.' He was amazed and said, 'Wow, let me see it!' "