Mrs Watty said Brittney's condition meant it was difficult for her body to make oxygen, so having oxygen bottles on hand was crucial.
"All our friends had oxygen bottles in their garages and they knew how to change a bottle over.
"She needed portable oxygen 24/7. Without it she would never have left the house."
Mrs Watty said oxygen bottles represented independence for her daughter.
"She was able to go to a movie, a school disco, a Stan Walker concert. For a while she was able to be a normal kid."
Although born and raised in Wellington, most of Brittney's extended family lives in Wanganui, and she considered it her second home.
"She loved to spend time at her nanas' place in Wanganui," Mrs Watty said.
Her grandmothers were Dot Watty and the late Pam Tuffin.
Mrs Watty said the family was "blown away" when they discovered BOC was interested in naming the new facility after Brittney.
"BOC hoped Brittney would be there to open it, but, unfortunately, she didn't make it.
"This centre is a tribute to an amazing girl," Mrs Watty said.