Generally you do not need to be court appointed to receive a tax refund. See the instructions for Form 1310. That said, the tax preparer may know a fact that requires the court appointment so you should ask him or her why they reached that conclusion.
If there are no private assets and there's an IRS refund you either have a joint account with the decedent or not. If she had a joint account with his name she can sign his name to the return & deposit the check into the joint account. If there is no joint account then she should be appointed Personal Representative.
It depends on what/how things were inherited. For example, was there a trust or were the assets inherited non-probate assets (i.e., financial account with beneficiary designation,...). If the Uncle had a will or had assets which are passed by probate, then a letter of appointment would be necessary. Whether there is a refund due is dependent on the Uncle's circumstances and past returns. I would ask the CPA for more details, if you are the person who would be executor of the estate, or else pass this information on to the executor. It is difficult to give you any further advice without knowing a lot of specific facts and circumstances, so I would defer to the CPA's judgment.
As indicated in the prior response, it may not be necessary to have a formal court appointment to obtain the tax refund. However, a refund check will be issued in the name of the estate. It may therefore be prudent to at least file a voluntary administration statement, death certificate, and Will (if the decedent left a Will) with the appropriate probate court, so that the refund check can be cashed without issue.
