The 78-year-old, who cannot be named for legal reasons, confessed in Wollongong District Court on Friday to molesting his daughter in the late 1960s, his eldest granddaughter in the mid 1980s and his youngest granddaughter, her sibling, around 2000.

All of the victims were around the age of five when the incest began. The abuse continued over a significant period of time, however was never reported to police.

The crimes only came to light in 2013 during a discussion between the mother and both her daughters.

The court heard the man suffered from an array of health matters including heart disease, hypertension, hyperthyroidism and osteoporosis.

He is also at risk of having a heart attack at any time, his doctors said.

The man’s lawyers sought a non-custodial punishment, however, Judge Andrew Haesler sentenced the man to an overall jail term of three and a half years.

He fixed a non-parole period of only 12 months after finding the man no longer posed a risk to community safety.

“It’s not at all impossible that any term of imprisonment he would not survive,” Judge Haesler said after reviewing the man’s lengthy medical records.

“However, courts must harden their hearts at times.

“People who commit serious offences against their own children and grandchildren can’t expect to escape punishment because of their ill-health or age.

“However, his illness calls for a degree of leniency on humanitarian grounds ... I will impose a significantly more lenient sentence than one that would ordinarily have been imposed.”

The man will be eligible for parole next September.