My aunt dies and has no children

Please accept my condolences on the loss of your aunt. I can't tell what your question is from your post. If your aunt made a Will, however, she was free to leave her assets to whomever and in whatever manner she wanted. She did not have to benefit all siblings, nieces, and/or nephews equally. If someone who would have been one of her heirs (the heirs are the people who would have received your aunt's net remaining probate assets if your aunt had no Will, not the beneficiaries of the Will) believes that your aunt may not have been in her right mind at the time she made the Will, or if the heirs believe that someone was exercising undue influence over your aunt so that the Will does not reflect her actual wishes, then they may be able to challenge the Will when it is offered for probate. To find out more about that, or to find out whether a given person is an heir at all (siblings would be, given the facts you state, but nieces and nephews would not be, unless there were one or more predeceased siblings who had surviving descendants), you need to discuss the situation with an actual probate attorney; preferably one with estate dispute resolution experience. This is not the kind of forum that allows an in-depth discussion of actual situations and the relevants facts for those.