I'd be doing the same thing if I was selling my horse. My horse has a history of problems that I have since solved, but if with the incorrect handler she very quickly turns into a dangerous horse. She is headstrong, pushy, obstinate, alpha mare. She is smart and knows her own way, and handling her is very different from handling other horses, as I have come to find out. She most definitely requires an experienced handler and rider.
That is why I would want to make sure that the new owner could handle her before I ever finalized a sale. Not that I could ever sell my baby!
This horse is a gelding, so the alpha mare theory is out the window for him. I very much doubt he has any real issues. If my own mare had been sitting for a year, she would let you hop on and walk around without fuss. But if you started asking for any real work, trot or canter or lateral and flexing and bending, she'd probably throw a fit.
I'm sure you will find out if this horse has any lemons on a two hour trailer out ride!
"You can do something wrong for thirty years and call yourself experienced, you can do something right for a week and experience more than someone who spent thirty years doing the wrong thing." ~WhattaTroublemaker