A clue to the seller's attitude about the future of the business is often the amount of seller financing being offered. If a seller is offering to help finance your purchase, there is probably no cause for alarm. Most sellers will answer honestly if you are persistent. An experienced broker probably knows the real motives for the sale and will give you straight answers early-on, if not to be honest and helpful, then to avoid embarrassment or to comply with disclosure requirements. Sometimes, however, brokers don't really understand a seller's motives, especially in the early stages of a listing.
Most sellers have difficulty expressing themselves when first asked.
You need to start asking this question now because you may have to ask it several times to get the complete answer. There may, in fact, be several reasons for the sale and you should know them all. My business broker colleagues have often confirmed my experience that even successful business searches can take many months. Many buyer prospects endlessly spin their wheels in business searches that do not produce results. Many waste time pursuing the wrong candidates because they fail to ask these simple questions.