Grace claims her older sister, Katie, is an “irresponsible and neglectful” mother who would rather spend time with her homeless boyfriend, Doug, than her two kids.

“Doug is a worthless, lowlife drug addict. He doesn’t have a job. Doug is homeless. He’s sleeping in my sister’s car. At one point, Katie and Doug were living in a tent,” says Grace of her sister’s long-term boyfriend. “When Katie’s with Doug in the tent, they smoke weed. Doug has told Katie he loves weed more than her.”

Katie denies her sister’s claims and disputes her characterization of Doug. She says she’s a hard-working mother trying the best to take care of her children.

WATCH: Woman Says She Wants Family To 'Back Off' And Let Her Raise Her Kids

Grace says she and her mother, Tara, are taking care of Katie’s 6-year-old daughter and 1-year-old son and say if Katie doesn’t get help, they will consider seeking custody of the kids.

“She has chosen Doug over the kids,” Grace claims. “It does piss me off. It’s not fair. Katie gets to go out and do whatever she wants to do. My mother and I are sitting at home with her children. I do feel like I’ve raised her children.”

Katie’s mom, Tara, says she calls Doug a “tick,” because he is “sucking the energy out of Katie.”

“I need for Katie to step up and realize Doug is a loser and be the mom that she can be,” Tara says. “I told Katie that if she didn’t get help, we were going to get custody of the kids.”

On Friday’s Dr. Phil, Grace and Tara confront Katie about her behavior. Does she say she wants to make a change? Check here to see where you can watch.