Their family members say the 16-year-old twins are bed-ridden, writhing in pain, most of the time.
What makes their case difficult is that the twins have a common blood drainage system for their brains and also only one of them has kidneys. Farah's kidneys are of great help to Saba who has none.
"We want death since we are fed up with our life. For the past five to six months, we have [experienced] pain all over our bodies, especially in joints, which has virtually left us bed-ridden," Saba told a local News Channel on Sunday.
The twins were brought into limelight six years back when they were offered financial help for their surgery after which their case was examined at a Delhi Hospital by Dr Benjamin Carson, a US neurosurgeon and director of paediatric neurosurgery at the Johns Hopkins Children Centre in Baltimore.
After examining the twins at New Delhi's Indraprastha Apollo Hospital on April 10, 2005, Dr Carson expressed hope of a successful surgical operation to separate the sisters.
But, the family rejected the offer fearing they could not bear the agony of losing one or both of their daughters during the operation.
As of now, however, family members are urging the government to arrange for their medical treatment or allow them to carry out their mercy killing.
"Right now, no body is coming forward to provide us with financial help to enable us to treat our twins. We are too poor to bear the huge medical expenses," Shakeel Ahmad, the girls' father, said.
The twins' elder brother Mohammad Tamanna said they wanted permission from the government to allow them to carry out mercy killing as his sisters' lives had become miserable.
"All the time, they [are] writhing in pain and we administer painkillers when the pain [gets to be] unbearable," Tamanna said.
"Instead of [forcing them to endure a slow death], they must be rather allowed to die at one go… Perhaps, that will be better for them, and us too," he said, in utter frustration.