[x] Let Eileen keep trying to calm him down
We can learn what we smell like later, from "Fiddle", since she's able to smell a true Hunter's moonlit scent. Or maybe I'm thinking of Adella (?) the prostitute, who definitely can.
I'd vote along with handing Eileen the music box, but I don't see how we can do that without Gascognoie seeing us do it.
Further, I don't know what good the music will do. Reminding him of his family at this point will just remind him that his WIFE is DEAD; the mother of his daughter IS DEAD.
On top of that, Papa G doesn't seem to think he's going to be around (or sane) much longer; that belief combined with the knowledge that his wife is dead equals "my daughters are orphans".
We need to see if Eileen can get Father G to focus enough on himself that he can grab his self-control back. The more faith he regains in his humanity, the more faith he regains in his ability to be a single father. THEN he can afford to really process the fact that he's a single father.