Murray had been hospitalized last week and died on Monday, Gibson shared.
“On behalf of my family and everyone who ever spent anytime praying for my mother, this is the saddest moment of my life,” Gibson wrote on Instagram. “My sweet Valentine just passed away.”
Gibson had previously shared his mother’s health battle and had asked supporters for prayers.
“May the lord Jesus Christ honor your walk with him and embrace you into the heavens,” he wrote, along with a video of himself holding his mom’s hand in her hospital bed.
“From here on I ask that you HOLD MY HAND MOTHER and never let my hand go………. Like you held my hand as a child and a teen never let my hand go mother,” Gibson added.
Gibson is the youngest of four siblings.