"I can ring her and she won't ever be upset about it. She is always there to help me and she has helped me get out of my shell and present myself comfortably,and be comfortable in who I am."
He's close with both sisters,with eldest Ally,who recently became a mum,also high in the teenager's estimations despite him being unable to resist a cheeky dig when asked if they spoilt him.
"I wish they spoilt me ... all I copped was some beatings,would you believe,"Cox joked.
"They have actually been really awesome ... they have been good to me,like another two mums.[They are] not afraid to have a crack at me and put me in my place."
His place in the AFL will be known on Wednesday night with the Bombers known to be keen on the athletic tall who can run two kilometres in six minutes and three seconds – and kick both feet.
Skinny enough to be nicknamed"Pencil",the Ivanhoe Grammar graduate put on close to eight kilograms in 2020 without losing his running ability after turning lockdown into a pre-season.
Twice a week he headed to Willinda Park,Greensborough,with his uncle,Bernie Smith,doing speed work one night and distance work another. In between he would do weights in the homemade gym and on the weekends trot 10 kilometres.
His dad,a plumber who played 30 games across eight seasons with Fitzroy,Melbourne and the Brisbane Bears,also reinforced to Cox what is required to succeed.
"I'm lucky enough that I am pretty talented,but I have had to work to become talented. It is an old cliche:[talent] is not going to get you anywhere unless you work hard,"Cox said.
He's not all work though,a vinyl collection of more than 100 LPs revealing his love for music,his comments displaying an innate sensibility:"You really appreciate music when it is on vinyl. I'm not sure what it is about,but you just do."
Cox is aware there is a wide world out there,laughing as he recalls his mother Julie,a hairdresser and make-up artist,surprising him recently when she casually mentioned she had once done David Bowie's make-up.
It's made him self-assured,yet curious,grateful and humble,aware his upbringing has prepared him to do one thing:work hard. His family thrives off each other.
"It is always a competition as to who is doing what the best,"Cox said.
"I'm very lucky and grateful to be bought up in the situation I have been."