YOU cannot find out whether the accountant filed an extension for your sister-in-law. SHE might be able to find out by calling the IRS. But it doesn't really matter. If the accountant did not file an extension, there's nothing you can do about it. It's too late to file an extension now. Your sister-in-law should just file her tax return as soon as she can. If she is getting a refund there is no penalty for filing late.
