What the judge said is true.
That said, if he believes his child's mother is endangering his child, by ignoring medical advice or giving her incorrect medication, he could take the child to doctors of his own choosing, during his visitations, for a second opinion. If he feels the child's mother is an unfit mother, he can petition the court for sole custody, assuming he is willing to raise the child himself, or he can try to get DCFS involved, if he can't raise the child, but believes that leaving the child with the mother is dangerous for the child. But those are very, very serious steps to take, and he needs to be prepared to spend tens of thousands of dollars in the fight, with little chance of prevailing. From the outset, he'll need an attorney, and money for investigators and experts. And these cases are so prejudicial and difficult, all those people will want money up front. And in the end, there is a 10% chance he'll prevail, and a 90% chance he'll get his visitation privileges revoked, and still be on the hook for child support to the mother. Men simply don't win these cases, unless the children are being kept in cages and fed dog food.
The one thing that helps nobody, is to become a frequent flyer in family court, without substantive issues affecting the child's welfare at issue. So, he cannot demand that his child's mother live a certain way, or raise his child in a certain way. Within the limits of the law for parenting, she has a right to be a bad mother, if that is what she wants to be.
He might also find that if he shuts up, pays up, and cuts contact with the mother, except for a bare minimum at the times he picks up and returns the child for visitation, that things go better. Often, young women will act out to keep up a fight with a former boyfriend, if that is the only way of being sure of his continued interest. Taking all the drama out of the situation leaves her with the realization that she is raising the child in a situation where nothing she does is going to get him back in communication, except through his attorney, and then, only on questions of the child's health and welfare. He may find that after months of this, his ex is suddenly looking for ways to share the child rearing burden, and is willing to agree to joint custody, or even to give up custody of the child. Many young women get to that point, when they realize how hard it is to find another guy who wants them and their child, as a package deal "instant family."
And then they'll both have a chance to move on with their lives, and do what's best for the child.
Australian Bar Association
Bar Associations exist at a Country level and also often locally such as Territory or State.