My one and only comment, @JuneBug75, is that it doesn't appear as if there was donative intent when the quitclaim deed was drafted (when the transfer was made).
Rather, it appears as if the brother expected something in return (i.e., to be paid for the share the brother purportedly transferred to the sister). If that's the case, then the brother (and sister) can dispense with filing gift tax returns (709s) and proceed with a different approach, such as a sales transaction.
