Ben Evison, seven, suffers from a muscle-wasting condition that is believed to affect just eight people in the world.
He has spinal muscular atrophy with respiratory distress type 1, or SMARD1, which leaves him unable to eat, sleep or play as it affects his respiratory system.
But his life has been profoundly changed after Rosie came into his life.
The 12-week-old puppy is being trained to help Ben get dressed, pick things up and will also be able to monitor his breathing. And since meeting, the pair have formed an inseparable relationship.
Ben's mum, Catherine, 39, from Whitchurch, Shropshire, told the local paper: "Although Ben goes to mainstream school, he struggles to make friends with the kids there.
"Now he has Rosie it means the world to him. Not only will she be trained to help him get dressed and monitor him, but she'll also be his best friend.
"The condition is extremely rare, and Ben has a different form that no-one else in the world is listed as having.
"We just don't know what the future holds for Ben. As parents it's very scary but we take each day as it comes.
"Doctors have told us to carry on as normal and obviously that can be difficult, but Ben is so determined to live so we will carry on as best as we can and Rosie will help with that."
Ben first developed symptoms of the condition when he was just six months old, but it wasn't until just a few weeks ago that Ben was finally diagnosed with SMARD1.
Catherine said: "By rights he should not be here, he shouldn't have survived past two years old. Doctors think the only reason he has done is because of his sheer stubbornness to live."
Ben is underweight because of his condition, and has a feeding tube and pump at night time. He has splints on his legs and struggles with walking, but he now has little Rosie his life has been transformed."
Ben's dad Paul, 47, said: "Me and Catherine get up in the night to check he is still breathing. He has a feeding tube and although he is still underweight the tube keeps him stable.
"We go into his room and his breathing is so quiet that we can't help but check that he is okay.
"Once trained, Rosie will be able to help monitor Ben's breathing in the night, as well as helping him get changed and go out."
Rosie's training is costing the family £31 an hour so they have started fundraising to cover the costs.
Paul said: "It's not that charities won't help us, they have said they will assist in any way they can. "We had to buy Rosie and I asked my boss for more hours because of the cost of training her.
"We would be so grateful for any money that we raise, Ben is so full of determination so we are just keeping positive for him and taking it one day at a time."
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