Zach needs to grow up!!!
His dad did nothing wrong, Zach is very entitled. His dad does not owe him anything, money property.
His dad has a right to get a fair value for the property. He does not have to give a family discount to his son.
How would it look for the other siblings if his father plays favoritism with him. He is being very selfish.
Now Zach is acting like a big baby and punishing his Family by moving away.
The dad is not the problem, it is Zach & his wife making it uncomfortable for every one