family visit visa granted but no relative in uk

Hi Guys,

can someone please help me based upon their experience or any such situation heard/observed etc

My friend applied his aunty's visa (mother's sister) she is unmarried and retired/old. By mistake he filled in family visitor visa form and submitted online instead of general visitor visa (he applied her general visitor visa in past and it was refused) His intention was to apply general visitor visa but drop down selection was not noticed and everything went wrong, anyway, he realised when application was submitted and I advised him to stay calm and wait with best hope (although as per my past experience, it was confirmed refused due to invalid category) but to my surprised, and his also, she has been grated family visitor visa

Now my question, when she will come to uk, is there a chance that ukba counter at heathrow may ask her whom she is going to visit and then realise that she is not family visitor but instead general visitor and refuse her entry in to UK? I know that they do ask couple of question in routine if the question is how long you will be here or where going to stay then all ok but if they ask whom you are visiting and who is sponsor and what is relation then she can not say son or husband's family as she is un married, any thoughts?

thanks for reading such a long post