Well, I guess this is more of a tolerance level issue as I would think with that argument, even making 1% profit off a person without telling them is not exactly ethical.
This case do sound hurtful to the heart because it involves a less informed elderly. You can look at it a few ways. If he was totally honest, and just chose not to mention particular numbers in order to keep his edge in his business, she did accept the offer he put forward and she is content with it. But if he LIED to get her to give the
property at that price, then that is an unethical act.
No matter how much profit a person makes, you cant really gauge the worth of his work.. as there are many job options out there and someone would always think his work is worth more and should be paid more...