Jealousy, probably. Kid was getting all the attention. You wouldn't believe how many ordinary people are possessed by demons and don't know it, until the demon in possession of them does something like this. Just watch, they will ask the woman why she did it, and the woman will say she doesn't know, she just saw herself doing it as if it were another person and she had no control. Its a sure sign of demonic possession. The demon was jealous of the kid.