Thank you everybody for your input. He won't be there- I'll email him when it's over.
I would think if you have sole legal custody, and he only has supervised visitation EOM, then he has no other right to your son than that. You notified him about the dental procedure, and I'd say that's about as much as you'd need to do. He can't demand extra visitation other times, why would this be any different?
or, rather, he can demand whatever he wants but you are only legally obliged to take your son to the EOM visits.
Robin~ single, work-at-home momma to my WonderBoys
YoungMan (6/00) & LittleBoy (6/04)
I think that legally, you don't have to let him come/tell him where it is since you have sole legal custody. Especially since he was ordered supervised visits (with a professional supervisor, yes?) and this would obviously not be supervised, I don't think you are at all obligated to do it.
I think the only gray area here is that he might try to spin this later on as an example of you keeping him away from his son if/when he asks for unsupervised visits. You are doing it for the right reasons, since it will only stress your son out, and I think that since you do have a professional witness from the visitations who can testify about the bond or lack thereof between your son and his dad, you will be okay.
FWIW it's worth, I think you are doing the right thing. If it was only upsetting to you to have him there, I would say just appease him and let him come, but since it will make your son upset and stressed and you are not legally obligated to invite him, I would not give him the details so he can go. It sounds like you did more than you legally needed to do just by telling him about it.
That said, I don't think you can stop him if he finds out where/when it is and shows up since there is no restraining order in place for you or your son.
I think if your son had a truly life threatening problem it would be considerate to let the other worried parent be there.
But this is a quick routine surgery. I don't think any court would judge you badly for following the current custody/visitation you have. I would just make sure it is not booked on his time and not give him specifics that would let him just show up.
If I were in your shoes, I would tell him that you are not deviating from the court order. And if the court order states that he is to pay a share of medical expenses, send him a copy and request reimbursement within 30 days.