I am happy for your client. I don’t know why in the world a parent would distance a child from the other parent... hatred, I guess. I have to also applaud your client working on allowing a safe relationship with the mom.
Why? Because they are moral reprobates. Sometimes it’s nice to see someone take a stand and refuse to allow another in their lives for a change.
Also, frankly, the chaos of back&forth really may not be worth it, and running into “others” that the parents get involved with, as well as chaos for any future children of those.