Sylvester Stallone’s wife of 25 years, Jennifer Flavin, filed for divorce on Friday

Sylvester Stallone’s younger brother Frank is showing support for the actor following news of wife Jennifer Flavin filing for divorce after 25 years of marriage.

In an Instagram post Wednesday, the actor/musician, 72, posted a throwback photo of himself and the Rocky actor, 76, when they were children.

“Brothers till the end! Enough said,” Frank wrote in the caption, adding the hashtags, “#brotherhood #loyalty #trust #family #god #country.”

Back on July 30, Frank posted a family photo of himself with Stallone, Flavin and their three daughters, Scarlet, 20, Sistine, 24, and Sophia, 25. “I had the best birthday ever with my family,” he wrote in the caption.

On Friday, Flavin, 54, filed a petition “for dissolution of marriage and other relief” from Sylvester at a court in Palm Beach County, Florida.

Flavin, a businesswoman and former model, exclusively told PEOPLE in a statement: “I’m sad to announce that after 25 years of marriage I have filed for divorce from my husband Sylvester Stallone.

While we will no longer be married, I will always cherish the more than 30-year relationship that we shared, and I know we are both committed to our beautiful daughters. I ask for privacy for our family as we amicably move forward.”

Stallone said in his own statement, “I love my family. We are amicably and privately addressing these personal issues.”

Stallone and Flavin wed in 1997 after first meeting in 1988 at a restaurant in Beverly Hills, California. They share three daughters: Scarlet, Sistine and Sophia. He is also a dad to son Seargeoh from his previous marriage to Sasha Czack. His oldest son Sage, whom he shares with Czack, died in 2012.

Sylvester Stallone and Frank Stallone in 2014. JON KOPALOFF/FILMMAGIC

Three months before the filing, the pair celebrated 25 years of marriage with loving posts on Instagram in May.

“Happy 25th anniversary to my amazing wife,” Stallone wrote in a caption at the time. “There is not enough words to describe what this incredibly selfless dedicated, patient, woman has meant to our lives and I only wish they could be another 25! Thank you sweetheart!”

Flavin then commented, “Thank you my love! I love you so much and we will be spending the next 25+ years together! Keep me laughing and I’m yours for the rest of my life!”

FRANK STALLONE/INSTAGRAM

She added in her own now-deleted post: “Happy 25th wedding anniversary to us! Thank you for always keeping me laughing, loving and protecting our beautiful family!

Our marriage keeps getting better every year! I can’t wait to spend the rest of our lives together!”

Alongside a photo of herself hugging her three daughters, Flavin wrote on Instagram Aug. 10, “These girls are my priority. Nothing else matters.

The 4 of us forever #truth #family #forever.” In the comment section, Sistine called her mom the “strongest woman I know,” and Sophia wrote, “You are our rock, cheerleader, and most incredible mom. We are so lucky to have you. Love you so much.”