Agents understand what it takes to get family members out of a home so that another person can come and view it. However, the decision to show a home ultimately comes down to the buyer's agent and their buyer.
It could be that they ran out of time for the day, encountered some other situation, or made a decision on another listing.
We recommend that you contact your agent for more information. It is possible that the buyer's agent contacted your listing agent directly to explain the reason.