I gave him primary custody (and, please, I don't want to explain that) but the divorce decree stipulates medical decisions are joint. So he cannot get them vaxed without my consent.
I do have someone who is my friend who has agreed to appear in court on my behalf to document how he was helping her with her new baby, they were talking about doctors and he tried convincing her NOT to vax. As she said,"He was very educated about it." (He maintains that he went along with non-vax and homeschooling because he was afraid of me. big eye roll I suppose if he could take back the homebirthing, he'd try that too)
All his international travel has been through his work so that will be easy to subpoena. My daughter has gone to Mexico twice & vax weren't an issue either.
I am thinking because I pointed out there was travel before and vax weren't an issue for him that he is going to back down from it. His lawyer may have told him he may have trouble with pursuing it too.
So, your problem is going to be that with him having physical custody, if you end up in a trial, the judge is highly likely to not decide on the Vax issue and just give him sole legal custody. Which means he will be able to do what he wants. His attorney is more likely to advise him of that, and he likely will pursue it. Knowing that now, I would say to negotiate a slow catch up schedule, agree on it, and keep your joint legal - cause if you go to trial there is a high likelihood of you losing joint legal and him ending up with sole. The reason for this, is that when parents cannot agree on important decisions, and end up litigating over them, its bad for the children (especially once they are old enough to pick up on whats going on - even when the parents are very careful of what they say to the children, older kids will pick up on the fact that there is ongoing litigation).
I'm sorry, family court issues are rarely fair, and rarely make sense.