"Train up a child in the way he should go: and when he is old, he will not depart from it" (Proverbs 22:6). That does not cover just right and wrong choices. That does not only apply to godly training. It includes watching out for negative influences. At the age of 24, "partying" with friends past young children's (single digit) bedtimes is more than just a disturbance of sleep. Taking the lifestyle outside the home to bring the result back in by coming home drunk, setting off home alarms, And the fact that she cannot be trusted to remain sober while babysitting is a hazard. Being messy and having a bad attitude is a negative role model as it is proven that children look up to an older sibling of greater age as compared to looking to rule setting parents. With that said, that does not mean to leave the step-child out in the cold, although he does have to be careful not to be encouraging bad behavior through his assistance. It was her choice to move in with a boyfriend and now cannot handle the financial impact because they broke up. Yet, another argument of why God intended for marriage and not cohabitation.