McKinnon fractured two vertebrae in Monday's clash against the Storm and remains in a Melbourne hospital in a critical but stable condition.
"I don't think there's much difference between them (the players) and your children," Bennett told KO FM, Newcastle.
"You spend so much time with them, particularly when they come to you young. I mean he was at the Dragons with me when he was only 17.
"So you have a fair influence on their life and they certainly rely on you for a lot of things, so it's only natural that they feel like one of yours, and that's what makes it a little bit more painful."
The seven-time premiership-winning coach admits Sunday's game against Cronulla at Hunter Stadium has been an afterthought this week and revealed the Knights won't turn their attention to the Round 4 clash until the day before the game.
"I haven't worried too much about keeping the players focused, it's about trying to let them go their own way without placing too much emphasis on whether we're playing Sunday or not, we'll worry about that Saturday morning," he said.
The Knights will pay tribute to their injured team-mate on Sunday afternoon.
McKinnon's number 16 jersey will be retired while players from his junior club Aberdeen will form a guard of honour when the Knights run out to face the Sharks.