"I almost died when I went to pick his things up and saw where he was living. You had to use a nail to get in and the open door rubbed up against his single mattress on the floor. The space was dirty and tiny and stunk. There were about 12 cats in there too. All his clothes were ruined. I couldn't believe it," she said.
Ms Boswell, 27, also fronted at court for the teen, who was sentenced to community service about a month ago on a wilful damage charge. She went to bat for him as well in talks with his youth worker about a carpentry, numeracy and literacy course he attends.
She had since talked to Masterton Mayor Lyn Patterson about a need in the town for a halfway house for troubled teens, and the Stand Up support scheme she founded with the help of friends, neighbours and Te Awhina Cameron Community House co-ordinator Donna Gray.
Ms Boswell, of Tuhoe, Ngati Awa and Ngati Kahungunu, was herself rescued, when adopted as an infant, from a family home in Levin where gang colours and codes had ruled - Black Power, Nomads, Hells Angels and Mongrel Mob.
"My mum's Black Power and my Dad's ex Mobster. That was their life. I have 16 brothers and sisters in my natural family, but only six of us are still alive.
"I'm really the only one who left the gangs and the alcohol and drugs behind. We stay in touch but they don't really understand me anymore."
Her parents resisted the adoption and threatened her adoptive mother, she said, who out of fear kept her mostly indoors throughout childhood, barring her from school trips and friends "because she was terrified they would find us and hurt us, or worse".
She had been "on the streets" since her early teens, Ms Boswell said, after living in a succession of North Island homes with her adoptive mother who, like her natural father, died last year.
The impending birth about four years ago of her eldest daughter, Cypress-Lee, had triggered her move to Masterton, after years of living at the Shepherd's Rest Boarding House for the homeless in Palmerston North.
She remained socially withdrawn after the shift until she made "the biggest move ever in my life" and took her eldest daughter to the nearby Ko Te Aroha Children's Centre. The decision led to a widening circle of friends and mounting involvement with Cameron Community House.
About 15 months ago, her second daughter, Leila-May, was born. Ms Boswell soon after began reaching out to teens who were struggling as she had at their age.
"Remembering those bad times woke me up and made me appreciate what I have today so much more. It's what's driven me to the work I want to do.
"I'm not afraid to talk about my life because I don't see it as something to hide.
"I don't look at the patches anymore, I've done my days. I look at the family, I look at the people.
"I don't care what patch you've got or how big you are. I'm here to talk to you."
Ms Boswell said some of the teens who visited her home faced family challenges but most "have no ears" and were simply at a wilful age.
She kept their parents in the loop about her involvement.
"I've been working on the idea for a support scheme, and a halfway house, for a couple of months now.
"It's intensified lately with people wanting to help out and get it started," she said.
"But for me, Stand up is about being strong and rising up wherever you find yourself. Stand up for yourself, your whanau, your dream," Ms Boswell said.