Hannah Robinson was a 19-year-old college student when her little brother TJ was born in 2017 and was soon placed in foster care because his parents were struggling with addiction issues.

Robinson knew then that she wanted to adopt him.

“I never imagined anything else,” she tells PEOPLE for a story in this week’s issue. “He needs someone, and I’m going to be that person.”

Robinson and her half-brother have the same father. “They’re not in a good situation,” Robinson explains of TJ’s parents.

Her father was also homeless – and Robinson knew that his parents were unfortunately unable to care for him. TJ was born prematurely at 32 weeks and was placed in various foster families until he was five years old.

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Robinson says she had “a wonderful mother, and if she hadn’t, I don’t know where I would be now, but I felt like it was my destiny to be that for him.”

She also knew that adopting TJ would take years. She told her boyfriend and high school sweetheart Drew Munn about her plan, saying, “You have to decide now – are you in or not?”

Munn, who had been with her since Grade 10, says he wasn’t sure at first if they were ready to be parents. When TJ was born, Robinson was a student at St. Lawrence College in Ontario, while Munn was attending the Royal Military College in Canada.

“We were still in college and gaining adult experience,” says Munn, now a 25-year-old engineer officer in the Canadian Forces. “But TJ needed us. Hannah’s conviction won me over.”

When the couple graduated from college, they bought a house and set up a room for TJ, expecting him to return to the family.

Over the years, Robinson, who works as a photographer in the Canadian province of New Brunswick, stayed in touch with her brother’s social workers and expressed her desire to adopt him.

“It didn’t feel like it was going to happen,” she says.

When TJ was in his last foster home, she was not allowed to visit him for over a year, she says. Then a new social worker was assigned to his case, who arranged a meeting for the siblings at a park.

“He came up to me and gave me a big hug,” recalls Robinson, now 26. “He said, ‘I missed you so much.'”

Robinson says the social worker told her, “You are TJ’s safe place. He doesn’t belong anywhere but with you.”

On October 5, 2022, 5-year-old TJ moved in with his sister and her then-fiancé.

A year later, in October 2023, at the couple’s wedding, TJ wore a tuxedo that matched Munn’s, wore his own wedding ring, and sat proudly at the newlyweds’ table, saying, “Our whole family is getting married.”

“He really saw it as his wedding,” Robinson says. “I love how we all chose to be together.”

TJ also has a close relationship with her husband: they wrestle, play video games and build Legos together.

“Every time he calls us mommy or daddy, it feels so, so special,” she says. (She and Munn are still in the process of legally adopting him.)

When someone asks TJ, now seven, to explain how he is related to Robinson, he says, “She’s my mother and my sister. And he thinks that’s wonderful,” Robinson says. “He thinks it just doubles our relationship and our love for each other.”

When she picked TJ up from school in January, she surprised him with a trip to Disney. A video she posted on TikTok has been viewed 40 million times.

“We had so much fun together. He talks about it all the time – he has his little piggy bank and he always says something like, ‘Look at the dimes I found. I’m putting them in the jar for our next trip to Disney,'” she says. “He really wants to go back.”

She shares her family adventures on Instagram and has also started a GoFundMe campaign for TJ to help cover therapy, sports, summer camps and college costs.

For the last few birthdays and Christmases, TJ has put a “little brother” on his wish list. He doesn’t have to wait long: Robinson is pregnant and will have a little boy on October 4th.

“TJ has brought so much joy into our lives,” says Munn. “We are so excited to continue growing together.”