"Joe and Jake are my stepsons. Niki is my husband's ex-wife and amazing Mum to Joe and Jake," she said.
"Niki continues to put them first throughout all of her treatment. Joe and Jake are also amazing big brothers to our 3-year-old daughter and she adores them as they do her.
"Money is running out and Niki may not be able to continue with her life-saving treatment.
"This is not an option - the boys need their mum and she deserves the chance to watch them grow into men and have their own families."
Clare is helping to raise funds for Ms Hitchen. Photo / Facebook
Hitchen was "completely overwhelmed" by Clare's generosity.