They're back in the care of their mama! While Lisa Marie Presley was focusing on her sobriety in rehab, her twin daughters Harper and Finley have been staying with their grandmother, Priscilla Presley. But now that the 49-year-old — who is also mom to Riley Keough, 28, and Benjamin Keough, 24, from her previous marriage to Danny Keough — has completed her months-long stint, she has regained custody of her eight-year-old twins.

"Lisa Marie couldn't be happier," a source tells Life & Style. "She's promised Harper and Finley she will never leave them again."

The mom-of-four has been reportedly seeking help at the Hills Treatment Center in Los Angeles. After entering the program, which allegedly costs $400,000 a month, in August 2016, Lisa Marie finally returned home in spring.

"It’s still a very family-oriented environment for them," Priscilla told Entertainment Tonight. "They’ve been with me for — it'll be over nine months. They're great. They're doing wonderful. They're living a great life. They see both their parents, and we'll see what happens."

Priscilla, the 72-year-old former wife of Elvis Presley, had been taking care of the twins in their mother's absence. Their estranged father, Michael Lockwood — who Lisa Marie divorced in 2016 — was only granted "monitored visitations" with his daughters, as news broke in early January that disturbing images of the children were found on his computer. Since the upsetting court documents were filed, Lisa Marie, Priscilla, and Michael have been entrenched in a nasty custody battle.

According to court documents obained by People, "Respondent [Lockwood] was discovered to have hundreds of inappropriate photos of children and is facing allegation of sexual abuse and neglect. While Respondent has yet to be convicted of crimes related to his possession of these photos, that he possessed them is documented evidence of conduct that has destroyed the mental or emotional calm of Petitioner [Presley]…"

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Lisa Marie Presley and Michael Lockwood in 2015.

Meanwhile, Lisa Marie has been engulfed in another battle, one against pill addiction. The singer and heir to Elvis Presley's $300 million estate, has been consumed with substance abuse. Over the years, Lisa Marie has been very vocal about her struggles with drugs. In the past, she admitted to Paper Magazine that she had used "cocaine, sedatives, pot, and drinking — all at the same time" during her teen years. "I just couldn’t be sober," she continued. "I don’t know how I lived through it."

"Lisa has completed her rehab and turned her life around," the source continues. "She's gotten a second chance, and she's vowed to stay sober from now on."

Despite the struggles each member has experienced in the last few months, the source tells Life & Style that the main priority of all involved is family. Moving forward, being a family is the thing that will unite everyone.

"She's open to working out a visitation plan with Michael," the source says. "Her main goal is to keep her family intact."