Fox has come into the Open on a wet sail, after successive finishes of sixth, fourth and fourth at the French, Irish and Scottish Opens.
Asked if he, or his wife would be more nervous during the Open, Fox laughed: "Probably me".
"It's nothing to do with us but you desperately want them to do well. You walk it with them.
"Last time he didn't know what to expect. He was terribly nervous. This time means just as much to him but he's more relaxed and part of that is security in his job, because of what's happened in the last three weeks," he added.
Fox said his son had a good team around him, which was important even though "he's the guy on the tools". He suspects his son has got a little bit of peace in his mind when you can relax and play as if with your mates.
"You've got to remember why you're playing the game. Because you love it.
"If you can find a little peace of mind that 'I'm going out and having some fun' that's gold."
Fox had found a house 10 minutes drive from Birkdale.
"Last time (at St Andrew's two years ago) there were 11 in the house. There's not as many this time," he added.
Fox is playing with prominent American Matt Kuchar and Scotsman Richie Ramsay in the opening round.