The idea behind step up visitation is to give a parent and a child a chance to bond and, sometimes, to see if a parent can follow orders regarding the child.
There must be an order in place if there is a child support obligation. If neither parent has a copy of the order, they can get a copy from the district clerk's office.
The ramifications of not adhering to the possession schedule will depend on why the dad is unable to follow the schedule and what the court's purpose was in establishing a step up schedule.
The parents need to get a signed order that outlines the step up possession schedule so that both parents understand the schedule and look to it for terms of moving to the next step. Right now it seems that there is a lot of confusion. It always best for the child if the parents work together "in the spirit" of the order (even if it's not signed). As the above attorney discussed, the step up schedule for a young child usually is meant to allow the child to bond with the parent and also provides milestones to show the Court the level of the parent's commitment to the child.
This is general legal advice. An attorney-client relationship has not been formed. Please contact an attorney for specific advice on your case.