No, I suppose it's no secret that Sirius was closer with James and me than he ever was with Peter, so suffice to say he didn't bring him around as much. James was more his brother and I...well, I suspect he felt sorry for me, really. Sometimes I wonder if we'd included him more, if he'd felt more like one of us, if he would have turned on us the way he did.
Don't apologise. Your future, my past, it's all an open book. Literally in some ways. If you have questions, if there are things you need to know, you need only ask and I'll help however I can.