The judge in their custody case will make sure of it.
"They'll be ordered to co-parenting classes if they haven't already," says Los Angeles-based family lawyer Scott Weston, who's not involved with the case. "Judge Scott Gordon will do everything he can to get their situation under control, turn down the heat, and get both sides focused on the best interest of the baby."
Judge Gordon is no stranger to high-profile cases, having overseen Britney Spears's divorce from Kevin Federline in 2006.
Gibson, 54, and Grigorieva, 40, will likely be ordered to attend anywhere from six to 12 group sessions separately, mainly to learn effective communication skills, which is a routine order in this type of case.
The ongoing criminal investigation of the ex-couple will proceed independently of their custody case, even if one of the parents could possibly face jail time.
"Whether they like it or not, Mel and Oksana have to get along for the rest of their lives because of their child," Weston says. "They have no choice."