But these are marriage rights, or should be civil-union rights as well...
For equality purposes in the marriage sense (with or without the use of the word marriage) gay couples should have the same rights as heterosexual couples...Thus why they are in the union or marriage together.
Household rights i also agree with, but in terms of a marriage equality debate, gay couples need to be granted the same rights as straight couples...Then it can be taken further outside of union and marriages, but at least things would be equal in terms of a union and a two person lifetime bond much like marriage. But these are the reason gay people are fighting for gay marriage is because these rights are not granted much like they are with straight couples..
Even if it is not marriage recognition, union recognition with equal civil rights is what is needed. And I don't care to even get married but i want the ability to have these rights.
So all people should get these considerations, but the fight right now is on marriage/union and a single sexual lifetime relationship. If that can't be held as equal in terms of a relationship earning these equal rights, then a brother and sister's household rights has even less chance as there's no union involved there which would be on par with a marriage union