Depending on the current state of the estate, it can vary. An estate attorney would be able to do it if all was in order and all heirs were accessible and agreeable in less than 4 weeks in most cases- sometimes quicker.
Great question to ask. Also, I'd ask if there is an appointed executor or administrator. This determines if one person can direct the process of obtaining the license. Also, estate law requires the appointed party to get the best price for the estate so until the sale is approved by the court (license to sell) they will market the home and present offers. They can be relatively simple transactions and lots of times I see well-maintained, solid homes that are maybe out dated but fairly priced. They will be the avocado green, shag carpet and wall papered properties if you want to recognize one. LOL
If your real estate agent is familiar with the process and asks the right questions to the right people. Hope this helps.