Mimi Kennedy, Anna Faris and Allison Janney

Based on the loglines for recent episodes of CBS' Mom, unfamiliar viewers may not realize that the show is a sitcom.

One recent episode saw Allison Janney's alcoholic character Bonnie relapse after two years of being sober, and in Monday's installment, Marjorie (Mimi Kennedy) is diagnosed with breast cancer. But part of Mom's charm is finding the humor even in horrible situations.

 Fall TV Report Card: How are the new shows doing?

"I think you can laugh the hardest when you get closest to something real," Kennedy tells TVGuide.com. "I personally don't laugh that much when I don't think the situation is going deep enough into something I identify with. ... I have family members who have been through this."

On Monday's episode, viewers also learn about Marjorie's strained relationship with her son, who has no interest in seeing her or hearing about her health problems. "I think when you hurt a child because you're an addict, that's a bad hurt because nobody else can stand in for you as a parent," Kennedy says. "Can you repair that? That's the question. And as long as there's life, there's hope."

Marjorie, a friend-turned-enemy-turned-friend-again of Bonnie's who meets Christy (Anna Faris) through AA meetings, is the stable one when compared to the mother-daughter pair, with 32 years of sobriety under her belt. Will the new information find her character also relapsing?

Photos: Surprising celebrity family ties

"That's interesting," says Kennedy, who adds even she is in the dark about where the  story line is going. "It is one day at a time. ... I think it's going to be about trying to get back what she lost, which was the ability to talk to her son. Whether she lives or dies, she would like to have that back, and whether she can get it back or not, I don't know. Other than that, she has to put up with her backup gang being Christy and Bonnie."

Check out a sneak peek of Monday's episode below:

Mom airs Mondays at 9:30/8:30c on CBS.

(Full disclosure: TVGuide.com is owned by CBS.)