She went on to detail that her dad taught her the importance of "strength when standing up for what I believe in", and to have empathy for all living beings.
"My husband amazes me every day with his kind and steadfast heart; his love for our daughter is infinite. My father-in-law works tirelessly for his family and is always there with a word of encouragement.
"These extraordinary men inspire me and I love them so very much," she wrote.
In the comments underneath the post, one fan asked why Bindi excluded her grandfather, Steve's father Bob, to which Bindi replied with a detailed response about their relationship.
In the since deleted response, Bindi wrote: "I really wish that my entire family could spend time with Grace. Unfortunately, my grandfather Bob has shown no interest in spending time with me or my family."
She went on to say that he has returned gifts she sent him after he opened them, and that he has ignored her correspondence from the time she was a little girl.
"He has ignored me, preferring to spend time doing anything else rather than being with me,” Bindi said.
"He has never said a single kind word to me personally. It breaks my heart."
She went on to write that her mother Terri still writes to him and sends him Christmas gifts every year, despite not receiving a response from him.
“I have struggled with this relationship my entire life and it brings me enormous pain.”
Bindi also claimed that her family has been supporting Bob financially since 1992 and are still sending him weekly payments.
Things didn't end there, but after opening up about her relationship with her estranged grandfather, Bindi went on to share a cryptic post to Instagram.
Uploading a photo of a quote by Steve Maraboli, the message that Bindi posted read:
“I don’t think people realise how much strength it takes to pull yourself out of a dark place mentally. So if you’ve done that today, or any day, I’m proud of you.”
The post follows Bindi's claims that her grandfather caused her "psychological abuse" for her entire life.
“Publicly he continues to claim that he wants to spend time with us while privately my entire life has been psychological abuse from him," she said.