Yes, of course it can be either parent trying to alienate the child(ren) from the other. Whether it be by bashing to the children the other parent, manipulating the child's thought process and perception of the other parent or by physically withholding visitation without a legal ok by the justice system. And I'm sure that I've left things out.

Only way to know if this family member is looking for help is to ask them why they are sending you this much literature.