Sealing is an ordinance (ritual) performed in Latter Day Saint temples by a person holding the sealing authority.[1] The purpose of this ordinance is to seal familial relationships, making possible the existence of family relationships throughout eternity.[2] Sealings are typically performed as marriages or as sealing of children to parents. They were performed prior to the death of Joseph Smith (the founder of the Latter Day Saint movement), and are currently performed in the largest of the faiths that came from the movement, The Church of Jesus Christ of Latter-day Saints (LDS Church). LDS Church teachings place great importance on the specific authority required to perform these sealings. Church doctrine teaches that this authority, called the priesthood, corresponds to that given to Saint Peter in Matthew 16:19.

https://en.wikipedia.org/wiki/Sealing_(Mormonism)

Feels weird to do something after people died when they haven't asked for it.... I can't confirm my mom would want this done..

Me and my mom and my grandmother were very close we all lived in the same area My mother and grandmother lived together and I was over there with them every chance I got until they passed..

The Mormon side of the family has always lived far away and have been sort of the call during the holidays family... That's another reason this feels so weird to me.... I barely know these people....

it is another meanigless ritual that will have no effect on the departed.

NO,I'm not sure she'd want to spend eternity with them. You may also include, it violates my firmly held religious believes.

But have lived among them for decades and from what I understand, the sealing thing is about their belief that they will be reunited after death somehow in mormon heaven or they get their own planet or some shit.

They do this all the time to dead people and basically they are claiming that these people have converted to mormonism after death, it's a big thing with them. They have huge centers where people can line up and "convert" dead people they never even knew. In fact there has been, and probably still is, a big push to convert dead Jewish people because the morons think they are the "lost tribe" of Jews. Seriously, that's what they do. The Jewish community is none too pleased about it and have said son publicly.

I'd tell them to go practice their insanity on someone else and decline the "offer". But if you have to live with them in your life, do whatever gets them off your back.

There are some unique oddities that are annoying, however...

If one is a Buddhist (or atheist, or non-theist):

I really, really don't think they have the power to influence where the dead go after life, especially to their imaginary celestial kingdoms. So why pick a fight over something so inconsequential?

If she (whatever that may be) died 8-9 months ago, she has necessarily moved on. Kind of a moot point.

Remember her with a peaceful and loving heart.

Mormon or legal, except to say I sense your consternation as to what to do at this juncture.

Seems most odd (to me, at least) that anyone (Mormon or other) would take it upon themselves to perform some (religious) ritual after a person has passed, unless that (passed-on) person requested same in a will or in some other legal instrument.

Also, what possible 'permission' could you give or offer (to give) that would be meaningful to anyone...other than to those (meaning, your aunt) whom this ritual is even necessary?

Further, what happens if she (your aunt) proceeds as she sees fit, even if you never respond...what jeopardy would she incur and how would anyone (especially in their church) even know what transpired between her (your aunt) and anyone else...unless she (your aunt) requests some form of legal instrument (from you) that might be presented to the church (elders)?

Sadly, like I said, I have no real wisdom for you (or for myself either).

...or at least mentioned it to someone.

Absent that you'll have to ask yourself if this is something that could have possibly offended her had it been suggested before she died. If the answer is yes, then it seems the proper thing to do is decline their offer. If you think she would have been for it or at least indifferent to it, then I don't see the harm. No sense in creating or contributing to a family rift when it doesn't really mean anything anyway.