"We have got photos, but having her on video was going to be really special. We made a really big thing of her 21st because we knew she was dying and wasn't going to have a wedding."
Mr Thomas woke about 5.30am on Sunday to find thieves had snuck around the back of his property and broken into the living area of his home, taking the red JVC video camera, an iPod and some cigarettes.
Hastings Police were investigating the burglary, but the sisters pleaded with those responsible to return the footage.
"I just broke down when I saw they had taken the camera," Mrs McGarth-Thomas said. "I don't care about the other stuff, they can keep that stuff, they don't even need to turn themselves in. Just leave the camera in the letter box or something."
Mrs Kerr said the footage was especially important to the family as Deanna's daughter struggled with her cerebral palsy.
"There was film of them together, special moments that we thought we would always have. With everything that has happened with my daughter and now Tynesha isn't doing very well, it is just so overwhelming and still so raw.
"It's just awful how someone can come in and invade your space while your asleep, but those things are not valuable compared to what we can't replace. You can't replace the photos and the footage, you can't get those memories back."
Mrs McGrath Thomas said the brazen nature of the burglary had also left her afraid in her home.
"It is hard to get your head around why they would come in while you are home. Is that what they were intending to do? They could have been up to anything."