For starters child support will be based on your son's income if she has the child which is usually 14% to 22%.And secondly if she hasn't used the other medical card there isn't much anyone can do.And text messages are considered inadmissable due to there isn't any proof who sent it anyone can use another phone and send a message.If there isn't legal documents stating every other year claim whoever claims the minor parent in custody of the child has legal right to claim