It is up to your daughter, if she wants to know her father and half siblings. YOU don't need to get involved other than to be supportive of your daughter and gracious to the half siblings if you ever meet them. To be honest, why does it matter why he walked away? Do you imagine that he will have a good reason other than he was selfish and wanted to do what suited him? Your daughter doesn't have to meet her dad, but she needs to make that clear to her half siblings, she can tell them: " I am ready to meet you and get to know you, but I am not ready to meet Dad." Thats it - set some boundries and stick to it. Good luck!
That's a raw wound to have salt just come waltzing back into out of the blue, so I can only imagine that it opened up a bunch of questions for you. Like RHR said, I would personally support your daughter in seeing the 1/2 sibs, while also backing her up on not wanting to talk to this man. However, I don't see any reason why you shouldn't talk to him, to ask questins or say anything left unsaid. Just don't expect the answers to be truthful if they come at all. And if you find it better not to talk to him, then I wouldn't. I'd talk about this with step-dad too, who will know you and your situation better than we do.
Thanks for the reply, I will support my daughter in what she decides to do, she is a grown woman now, at the age of 30 she is more than able to make those decisions on her own. i do not expect ant truthfulness on the biological fathers part at all.
What happens is that people start aging and start remembering the things they have done in their past. Your child is one of those. It is COMPLETELY up to her. Some people have a real strong need to meet or know their biological parents.
I have never met my bio father, nor do I ever plan to and if he ever contacted me I would tell him just that. I have no desire to re-connect with the male that adopted me either. I have his last name and that is the only connection we have.