OYOYOY made a good point, though I would not let that stop me from trying to be of help. HOWEVER, there is a phenomenon that some women feel threatened by the presence of a divorcee in their homes. There unfortunately IS some valid reason for that, because there is a certain type of divorcee who lets her dependence on the helpful male neighbor become something else. Sometimes lines are crossed, not even necessarily aveiros chas v’sholom, but just neediness that becomes inappropriate.
I am not accusing any divorcee of seeking to cause sholom bayis problems for others, but it sometimes does happen even innocently, and it makes some wives wary. That said, I have friends who are divorced, and we have maintained spearate relationships with both ex-husband and wife.
You just have to know where to draw the line, while at the same time being reasonably supportive. Yomim tovim can be especially hard, if the children are with the non-custodial parent.
Just use seichel, and offer that help or invitation, but as an adjunct, not as a substitute.