Teddi Mellencamp has demonstrated exceptional courage as she confronts brain tumors, fully supported by her family, with her musician father, John Mellencamp, offering positivity and prayer throughout, a source exclusively shares with In Touch.

“John has been an incredible dad; he immediately rushed to her side and went straight into protective mode,” the source reveals. “Despite their ups and downs, he’s always there when she needs him, and this time was no exception.”

“Although she has children of her own and is in her 40s, she remains his baby girl, so he’s been quite emotional,” the source continues about the reality star, who has daughter Slate, 12, son Cruz, 10, and her youngest daughter, Dove, 5, with ex Edwin Arroyave. “He’s kept it together to be her pillar of strength, but it has not been easy.”

The source explains that the “Hurts So Good” singer, 73, was “understandably terrified” before his 43-year-old daughter’s major surgery, but notes he “refused to let her see the fear and just kept telling her that the surgery would go well and she’d come out better than ever.”

“She did come out, but she’s been in horrible pain since then, which is very hard for John to see,” the source adds. “He can’t wave a magic wand, or write a check, to take her pain away. All he can do is make sure she’s getting the best care and also be there every step of the way to hold her hand.”

As In Touch previously reported back in February, Teddi told her fans that doctors discovered multiple tumors on her brain that had been “growing for at least six months” after she told them she’d suffered from weeks of “debilitating headaches.”

“Two of the tumors will be surgically removed today,” she wrote via Instagram at the time. “The remaining smaller tumors will be dealt with via radiation at a later date.”

A separate insider said Teddi had a “long, tough road” to recovery ahead of her on February 25, but after spending more than two weeks in the hospital, the Real Housewives of Beverly Hills star shared she was allowed to return home on March 4.

Despite the procedure’s success, three more tumors were found in her brain and two additional lumps were discovered in her lungs at a post-op follow-up appointment.

Amid all the ups and downs, on her first podcast episode since her surgery, Teddi confessed her father’s help has “really been a game changer” for her as she continues on her health journey.

“On my darkest, saddest days, I think I’m dying,” the reality television personality explained during her and fellow Bravo star Tamra Judge’s “Two Ts in a Pod” podcast. “I can’t see. I can’t walk. I can’t even get out of bed. I remember feeling like, ‘This is actually it.’”

“Right now, I’m starting to see the light and I’m starting to think about the future,” Teddi added.