I was wondering if I could adopt my boyfriends siblings and how would I go about doing so when I live in another state than the siblings. They are currently in foster care, And there parents rights have been terminated.

You boyfriend would have to file for custody of his siblings.

Depending on your location you my be able to adopt them once he has custody. You will probably need to be married first.

If you were to adopt your boyfriend's siblings, that would mean you then have an ongoing domestic &/or romantic relationship with your children's brother. Slightly, er, weird, would't you say?

That is, of course, unless he were to adopt them too.