T/E attorney here.This is a state-specific issue. You should ask the attorney what the next steps are. Here, we would file a petition for court approval of the accounting and fees, and a court order closing the estate and releasing the executor. The attorney wouldn’t be entitled to indemnification. Any of the heirs or beneficiaries could raise any objections they may have, and the executor could reply. There might be a hearing if there were factual questions, or if not, the court would decide on the law. But I don’t know what your state’s procedures are.
Re: the sibling wanting to sue the attorney, on what grounds? If they disagree with the fees, that is one thing, but if they claim the attorney committed malpractice, that’s another. On what grounds do they claim the attorney’s actions harmed them? The attorney and the executor need to assess the risk of a suit, determine whether the suit would be something that would be appropriate for the esate to pay to defend (in which case the estate may have to stay open and keep back sufficient funds to pay for the defense until the statute of limitations has passed), etc. It may be that the grounds for a lawsuit can be removed by a formal closing of the estate, or not, depending on the basis of the claim. If the attorney believes there may be basis for a valid malpractice claim, s/he may have a duty to advise the client of this and advise them to seek other counsel to evaluate and advise.