Interpreting Art Works of Children

While I was researching online for interpreting children's art, I saw this sad story of a babysitter who found a disturbing drawing from the kids. Their parents are going though a divorce. I am still searching the answers to her questions. Please read, maybe you can help.

Hi. i need some help... im a college student who is going into art therapy. I have been babysitting two boys (age 5 and 3) for a a year now and a few months ago problems have been occurring in their home and the parents are now currently going through a divorce. Although it is really not my place to say whether or not i find a parent to be a good or bad one, but i feel that their mother is not living up to her responsibilities as a parent. The story with her is long and complicated and i feel she has psychological issues to deal with within her own past and childhood (her parents were also divorced, and i heard stories of psychologically abusive things her step father would do to her). She doesn't physically abuse the children but the fact that she is a stay at home mom and has 4 babysitters including me, and we all seem to work long hours for her (9-12+ hours and even do several overnight stays) and that the kids say they miss mommy and have become violent to me, punching me when she leaves, makes he think that the lack of times she spends with them is some how becoming the abuse. Their father works many many hours and goes on several business trips to support their wealthy life style, and their mother only allows the kids to stay with him every other weekend. One weekend, their mother decided to quickly move out of their large house with the boys, without a word, while their father was on a business trip, he was furious to find she had taken such a drastic step without giving him any reasons. Lately i have noticed their drawings have changed, especially the 5 year old. he draws pictures of the large house with rain clouds and stormy weather and drawing pictures him holding hands with his father and his mother at the bottom corner of the page (when asking him to draw a family portrait). Well, the real question that i have is that i heard once that when a child is drawing a picture of the house they live in, and you give them a variety of colors to choose from, if they decide to draw the house in red and green its suppose to be a bad sign or a sign of some sort. Is that true, given the knowledge that they have been acting differently since their parents have been apart and the little time spent with either parent?