Albert Grannon, 78, will be sentenced at Sheffield Crown Court today after he pleaded guilty to the manslaughter of Stanley Metcalf and the possession of a firearm without a certificate.
Football-loving Stanley was fatally shot in the abdomen by Grannon with an air rifle at his home in Church Lane, Sproatley on July 26, last year.
Humberside Police previously said Grannon had shown no remorse, until he pleaded guilty at a court hearing last month.
Stanley's mum Jenny Dees, has now called for the judge sentencing her grandfather to send him to prison.
She said: "For me, I don't believe he should be coming home.
"I believe there should be a punishment there. I do believe he does need to go to prison and take responsibility for the death of my son. He did cause the death of my son."
Miss Dees says that in the 11 months since Stanley's death, Grannon has not once apologised to her for killing her son.
She said: "I have had no remorse shown to me. I have had no apology and that is unbearable and unbelievable to see.
"I loved and respected my granddad so much and the day Stanley died I thought he would come to me and say he was sorry, why wouldn't he? But he didn't.
"People say he is in shock and that he will say sorry afterwards. We are nearly up to a year now and he hasn't.
"I do believe that if you cause the death of somebody, regardless of whether you meant to or not, there should be a punishment in place and that is going to prison."
Stanley's family have since set up Stanley's Law in his memory as they call for more regulation over the sale and use of air powered weapons.
The law in Scotland states it is an offence to use, possess, purchase or acquire an air weapon without holding an air weapon certificate.
Miss Dees is campaigning for the same law to apply in England and for people to be more educated when it comes to using and owning air weapons.
She said: “I want more awareness and education around air rifles and more training around them.
“My personal opinion is that it is too easy to go into a shop and buy an air rifle with a few little bits of ID and be able to walk out with an air rifle that is -12ft/lb and under and go with it.
“I am trying to change the law around that and get the right education in place.”
The petition has since gathered more than 5,700 signatures since it was launched late last year.
Miss Dees said: “It shouldn’t have taken the death of my son for laws to change.
“His life was taken away and that is due to the fact that people are handling air rifles that are -12ft/lb and under without any training.
“I do believe there needs to be a law in place for training and education.
“People say there is no danger in a rifle like that, but I have the evidence to proof there is, my little boy is dead.
“I can’t bring Stanley back, but if this campaign and petition stops just one person losing their life it will be worth it.
“I promised Stanley I would do this and get this out there so nothing like this would ever happen again.
To sign the petition, click here.