The cash was split by lottery organisers down the middle, with each scoring NZ$671,500.
But moments after they were pictured with their prize, Ms Reddick, who lives in the small town of Margaree Forks in Nova Scotia, turned to her nephew and uttered four brutal words: "See you in court."
From that moment on, the pair were engaged in a nasty public feud.
Ms Reddick argued she never agreed to split the money with the teen, claiming she had only transferred him C$100 to buy the tickets on her behalf, and asked him to include his name on the ticket for "good luck", according to The Telegraph in the UK.
The CBC network reported the 57-year-old as saying her nephew "didn't deserve" the cash.
"He's dead to me," she said at the time.
"I bought the ticket. Now he's trying to lie and say I said 'split' the winnings.
"I put his name on the ticket for good luck because he's like a son to me — he was. He was lucky, but not for half a million dollars. Tyrone is getting nothing from me."
Ms Reddick contacted her lawyers, and last month, Supreme Court judge Patrick Murray froze half of the winnings — Mr MacInnes's share — while the dispute was dealt with.
Now, it has been revealed the family has finally reached an agreement and will avoid court proceedings. Under that agreement, Ms Reddick will pocket the bulk of the winnings — around NZ$1m in total.
It means her nephew will receive just NZ$407,800 — a little more than half the money he was originally awarded.
In a statement emailed to The Globe and Mail, Ms Reddick's lawyer Adam Rodgers said both sides were happy with the result.
"The parties are pleased to announce that they have reached a resolution … They are both satisfied with the terms of the settlement," the statement read.
"It was reached mutually in order to avoid further court proceedings and to bring this matter to a final conclusion.
"Both parties are looking forward to putting this matter behind them, and no further media statements will be made."
But many members of the public claimed Mr MacInnes deserved half the jackpot, with many slamming Ms Reddick for her "greed" and "shameful behaviour".
After posting a photo of Ms Reddick and Mr MacInnes on Facebook back in July, the lottery's page was flooded with opinions from strangers regarding who was in the right.
"Wow … this is such a sad case why are people so greedy. Just be thankful for what you have," one woman posted, while another wrote: "She is lucky I am not the judge who will be presiding over this case because I would give the kid 75 per cent of the winnings so hopefully he can better his life."
