The devastated couple have urged families to consider the option in the event they are confronted with a similar tragedy.
They recalled that just before he died, Cillian was starting to become familiar with cartoon characters like Buzz Lightyear.
"He often proclaimed himself to be a 'superhero'. Thanks to the staff of Crumlin hospital and the transplant co-ordinator, we were able to give Cillian the opportunity to be a real superhero and his legacy lives on with those that he has now helped," Mr Minnock said.
"We would encourage parents to consider the what-if scenario in the event that they had to confront the horrific situation of the loss of their child, (to think) of the other families they could possibly help through organ donation."
Cillian, who would have turned three today, was rushed to Tallaght Hospital and later transferred to Crumlin Children's Hospital after suffering a brain haemorrhage.
Sadly, there was nothing that doctors could do to save him.
In the aftermath, Crumlin hospital assisted Donal and Elena with their son's participation in the Beaumount Hospital organ donation programme.
Cillian initially collapsed in his bedroom on the night of October 10 and within minutes had stopped breathing.
Elena desperately tried to revive him, administering CPR under the instructions of the emergency services over the phone.
The ambulance was on the scene minutes later. Emergency personnel commenced resuscitation at the house and continued on the way to Tallaght hospital.
Cillian was later transferred to Crumlin hospital as soon as he was considered stable enough to be moved. He was maintained on a life support machine in the intensive care unit but tests confirmed there was no brain activity.
He was pronounced dead on the morning of October 12.
A scan later established that little Cillian had suffered a subarachnoid brain haemorrhage and had likely died within minutes of his initial collapse.
Mr Minnock, originally from Enniscorthy, Co Wexford, praised the medics in Tallaght and Crumlin.
"The staff we dealt with at both hospitals were terrific. We particularly found the staff of PICU 1 (intensive care unit) in Crumlin hospital to be exceptional and extremely professional in their dealings with us and we really couldn't praise their handling of the situation highly enough," he said.
For further information on organ donation visit www.beaumount.ie or www.citizensinformation.ie.