Both are victims but the child is a victim of the lying mother that committed fraud and the man is a victim of the paternity fraud committed by the woman.

They are victims of a different thing and both deserve help but most people tend to ignore the problems for the man and ignore that paternity fraud affects people differently.

The child still has their mother, their mother's family and in more cases than people would like to admit they also have their biological father and their family.

The man in general has to deal with losing their wife, losing who they believed was their children, with depressing, anxiety and even worse in cases like my friend.
The one that sever the bond with the child DON'T DO IT consciously, it's a defense mechanism to deal with the huge amount of pain from the lies and deceit. For some it's like their real child died and they can even grieve.

Both the child and the victim of paternity fraud need a different kind of help and for a LOT of them part of the help is being able to leave the child life without being called a monster, cold blooded and being told that they are less important.