Yikes, probably the sort of conversation that should have happened before committing to marriage, but what is done is done.
Your friend needs to discuss his desire to have children as soon as possible, but to approach that conversation equipped with options that do not involve her being pregnant (surrogacy, adoption etc...). It might be that her Tokophobia can be overcome with therapy, but I'd prepare for a scenario where it cannot be overcome. Also, he needs to talk to her to ensure that she does want children, and that the Tokophobia is the only barrier to this.