Judge John Bergseng agreed and said the offending around the will had "sinister overtones".
The court heard how the victim uncovered the offending when his bank card declined and he then involved the police.
After hearing MacDonald had looked to change his will, the pensioner noticed his smoke alarms were missing.
"That's obviously caused him real concern as to what you might have been planning," Judge Bergseng said
However, the judge stressed the only charge in relation to that was accessing a computer system for a dishonest purpose.
Court documents show the offending began in March when the victim was hospitalised several times because of falls.
MacDonald stole bank cards, applied for other credit cards, set up internet banking accounts and over a three-month span made 360 transactions, depositing more than $60,000 into his own bank account.
When questioned, he told police he had spent the money on "personal items for himself and his family" but today the court heard how the defendant had a gambling problem.
His lawyer Kathryn Penrose said her client had been to Gamblers Anonymous but Judge Berseng described it as "too little too late".
On June 5, MacDonald applied for a will through Perpetual Trust Ltd in the name of the victim.
On the form he assigned himself as the executor of the estate and the $150 fee for the service was paid, like everything else, using the man's credit card.
MacDonald, who has 15 previous dishonesty convictions, admitted the offending as soon as he was confronted by police but with regards to the will said: "I wasn't going to go through with it."
He told the court today he had sent an email to cancel the application a day after he made it.
Judge Bergseng ordered MacDonald to pay $1300 to the victim and $20,800 to various banks he ripped off.
He was jailed for two years and four months but before being led away, he asked to address the court.
"I'm sorry for what I've done. Not because I got caught but because of the people I hurt, especially my family and friends and public. I'm sorry, I really am."