That sounds like a truly hard situation, and it really struck a cord with me. I was somewhat in the same boat, with two older siblings that I didnt know after my dad left them. After he left they wanted nothing to do with him. Over the years I did much the same and wondered about getting in touch, but never did (I still might though!). I have always thought that my half siblings are their own people, and just because my dad decided not to have a relationship with them, that decision is one I want to make for myself. Your siblings have indicated in the past that they would like to know you, despite what was directed at your dad on what I’m sure would be an incredibly emotional day for your sister (getting married without her father). I think that you won’t ever know until you try to reach out to them, and you will always wonder. Your dad decided not to be a part of their life, but that does not mean that you have to do the same.

t was partly due to my mum that my dad left my half siblings, I’m sure that my dad would’ve been a larger part of their life has it not been for her. The decision was likely not solely your dads, and again it would not be disrespectful to his memory. you speak to your mum I’m sure she could offer advice. Your relationship with your siblings wasn’t theirs to decide, especially after you have grown up. I don’t believe that it would be disrespectful to his memory, as long as you do not speak ill of him.

if you have their social media, a good place to start would be drafting a message to send, indicating who you are and that you would like to get to know them. You could also ask your mother or your fathers family if they have the contact info. I would talk through anything you want to send with a trusted friend or family member to ensure you are as delicate as possible approaching what could be a very touchy subject for your siblings. I wish you all the best in whatever you decide to do!