McAvoy spoke at length about the 86-year-old tycoon at Thursday morning's pre-match press conference for the Championship clash with Derby County.
One line from the Scot about Hemmings' dedication to PNE particularly stood out, McAvoy saying: "Some of us are passing through but for others this is their life. It was his life."
North End host Derby on Saturday, with tickets prices cut to £5 and all gate receipts being donated to charities supported by Hemmings.
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McAvoy said: "It was a shock for everybody. He was a wonderful man, I don't think anybody can sit and tell me any differently.
"In my book I class him as a Preston legend. I think it was 48 years, his time involved in the club, that was incredible.
"We owe a lot to him, everyone involved in Preston. You just need to look at our visitors on Saturday, Derby County and the difficulties they have been in.
"During Covid-19 which was difficult for everybody, Mr Hemmings made sure that everyone at Preston North End received their wages which is testament to the type of person he was.
"It is a poignant and fitting tribute which the club have done for him on Saturday, £5 a ticket for everybody including the away support.
"For the money to go to charity shows the type of person he was.
"He will be sadly missed but he won't be forgotten,
"I'm in privileged position, a lot us that are here who work at the club are privileged to be here - the players that wear the jersey.
"This is a real family club and that is the feeling you get.
"Trevor Hemmings deserves nothing better than the people of Preston to come out on Saturday to say thank you and farewell.
"It has been a tough couple of days to be honest.
"But Kathryn Revitt his CEO and the Hemmings family sent a message to us all, Peter Ridsdale spoke to us a group.
"He would have asked for business as usual. Our task here is to try and win games, win as many as we can and be as successful as we can.
"They were the resounding words he used to tell me.
"I met with him as recently as Wednesday of last week, he was here during the international break. It was great to see him.
"He was 86 years of age but you would never have known he was 86. He always kept us on our toes.
"It was great to see him come in, it was a breath of fresh air. The players loved to see him and he loved to see the players as well.
"He used to tell us how he thought we had done, good or bad. He's wanted nothing more than success for Preston North End.
"We have a chance now to try and make it as successful as we can.
"Mr Hemmings would have been desperate to see Preston in the Premier League, I don't think there was any doubt about it.
"He shared that thought with loads and loads of fans. It has been mentioned to me loads of time that we are one of the only Lancashire club not to have played in the top flight.
"That was something he was hoping he could see done in his lifetime. Unfortunately he never got the chance to see that day but I'm sure it will happen one day.
"That is what we need to strive to do, to remember him, never forget him, do the best we can for him.
"Some of us are passing through but for others this is their life. It was his life.
"For us guys who are passing through and have only been here a short space of time, we need to understand the importance it is to people who have followed and supported the club and in Mr Hemmings' case, saved them.
"Let's make sure on Saturday we give him a fitting tribute, that is my rallying call to the supporters, the players, staff and everyone involved in Preston.
"Let's be the best we can be."
McAvoy said the North End squad had been shocked to get the news of the owner's passing on Monday night.
But their focus was now trained on taking on Derby.
"You could see some of the players were hurt and shocked," said McAvoy.
"He phoned here every day, he spoke to Peter every day on the phone. Every decision made at the club, he was there, he was hands on.
"Some owners of clubs are distant, he was never distant."
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