The Malfoys are not so secure in their place as they once were. To put it baldly.

And Rosier... Well, he's the sort to stay out of the way when the wind's blowing change.

As for Finnigan, it's fine to have pets, Padma, but don't confuse that with anything more. Rosier's fostering him because they need to control the Irish situation, and in Ireland Finnigan's family are all that. But, really, that tells you all you need to know: he's Irish and will never be more. On top of that he's a halfblood. So if he entertains you, fine. Only, don't get carried away with his bollocks about being a prince of the Irish. This isn't a romance novel we're living in.