One segment about the child/parent roles being reversed:
Parents are the guardians and caretakers of children - they care for the emotional and physical needs of a child to ensure that the child's needs are met. However, for some, the traditional roles of parent and child are not followed. Parentification may be defined as a role-reversal between parent and child. A child's needs are sacrificed to take care of the needs of one or both of his or her parents. In very extreme cases, the parentified child may be used to fill the void of the parent's emotional life.
During the process of parentification, a child may give up his or her needs of attention, comfort, and parental guidance to care for the needs and care of logistical and emotional needs of his or her parents.
The parent, in the case of parentification, does not do what he or she should do to take care of the child or children as a parent and instead, gives up parental responsibilities to one or more of his or her children. Thereby the children are "parentified." During parentification, the child becomes "the parental child."
In a list of "types" of parents where this often occurs is "Alcoholics".