Hi Hometown girl
Welcome to the forum.
Yeah I can identify with your feelings there - my father is also narcissistic although it's my mother that I suspect (am pretty sure) has BPD.
i admire your grit in standing up for yourself and your family. I know how hard it can be as you are challenging ingrained feelings that have been instilled for so long.
I agree with Turkish that yuor kids should be the ones to decide how to proceed as far as his presence at their weddings. it would be well worth keeping in mind that there are ways to minimise impact of bad behaviour and it is worth preparing strategies beforehand just in case.
I am also concerned with his characterising it as a 'mishap.' That is definitely not taking full responsibility.
Regardless of what your sister or indeed anyone thinks is the cause, it is probably worth just trusting your own instincts.
It's great that you are making boundaries and being specific about what you want and what the consequences will be whatever he decides to do. That leaves it clear for him to make his own decisions whilst protecting your own needs.
As well as the article Turkish I posted, I would recommend reading more about fear obligation and guilt which will help you define how those behaviours impact on you. The link is here:
Article 16: Emotional Blackmail: Fear, Obligation and Guilt (FOG)You mentioned that you would like new perspectives - do you feel the ideas you have now aren't serving you? What would you like to try and achieve? Any extra detail will make it easier to provide you with support that will help
All the best
Ziggiddy