Thank you for using JustAnswer.
I'm sorry to hear about your situation. I assume that there is a court appointed executor here, correct? That is, it's not enough that there's a will in place that says "John Doe" is the executor. That's merely an expressed preference by the testator as to whom will serve in that role. It still needs to be appointed by the court.
Now to the extent that there are decisions to be made, it's really the executor that makes them. It's a good thing that the heirs vote on what to do, etc... but they don't legally have a right to do so. The administration of an estate is not a democracy unless all the heirs are co-executors (and that's a real mess). In such a situation, the three children would only get what the deceased brother would have had. They would not have equal votes with you and the other siblings, but their three "votes" would combine to be one "vote" and that one vote would still be on par with the other votes. So there would not be 7 votes now, it would still be 5. But again, that's only in the situation where they're given a "right" to vote, and that would be if they're joint executors OR if the will gives them that right. Otherwise, the executor appointed by the probate court would have the ability to make these decisions, and if the other heirs don't like it, they'd need to file a motion with the probate court to remove the executor or at least make the executor do something different.
Hope that clears things up a bit. If you have any other questions, please let me know. If not, and you have not yet, please rate my answer AND press the "submit" button, if applicable. Please note that I don't get any credit for the time and effort that I spent on this answer unless and until you rate it positively (3 or more stars). Thank you, ***** ***** luck to you!