First port of call is Legal Aid. At the very least, they can provide legal advice for free on up to three occasions for a single matter, but they can also organise family dispute resolution, which is the first step toward getting the matter resolved, be it by way of agreement between the parties, or by way of Court. The father may also be eligible for Legal Aid funding for representation in Court.
Alternatively, in the event that agreement can't be reached between the parties and he does decide to pursue the matter at Court, he can consider self-representing. There are many invaluable resources available online, including LawAnswers.com.au, which can help your friend through this process.
About family dispute resolution...
It's mandatory that parties attempt to resolve their dispute between themselves before they are permitted to seek arbitration by the Court. A family dispute resolution conference is the best opportunity for this to happen, as it's overseen by a neutral third party whose goal is to keep the parents on point and keep things civil. It's common for parents to seek legal advice before a family dispute resolution conference takes place; it's also common for parents to have a lawyer each present during the conference.
The benefit of your friend's ex actually getting legal advice is that she will learn very quickly that withholding a child from an involved parent is a huge no-no in the view of the Court. Unlike State Courts, the Family Court is significantly less tolerant of claims of 'harassment', especially when such harassment has been only in regard to the child. However, the last thing your friend wants is the ex to go pursuing a malicious restraining order against him, because it creates an unnecessary obstacle that will result in more proceedings than is absolutely necessary.
As such, so it would be wise to minimise contact with the ex, and instead follow the more formal avenues of resolution, namely contacting Legal Aid or Relationships Australia for a family dispute resolution conference. Both Legal Aid and Relationships Australia will do all of the legwork for organising the conference, including contacting your ex. If the ex refuses to participate, your friend will receive a s 60I certificate, which paves the way for him to file an initiating application with the Court for parenting orders.
If I may, what were the care arrangements like before his time was obstructed by the ex?