His Grandfather is the head of the company. He's 90 and I've seen and heard from him less and less. The grandson is the future of the company for sure. There are people within the company that I deal with on a daily basis but the grandson oversees most everything. He can be a decent guy but he can be a tyrant sometimes.
Best of luck.....
In the end, if you are not comfortable with how they act, then do not be a part of the situation
Create an order of operations, what is done in each step/stage, and listing what is needed at each step to move to the next stage (from both parties)
ask them if they have suggestions to improve the efficiency that allows ALL parties a good relationship
A good rule to implement from Tim Ferriss
The Customer is Not Always Right — “Fire” High-Maintenance Customers:
Not all customers are created equal. Apply the 80/20 principle to time consumption: What 20% of people (customers) are consuming 80% of your time? Put high-maintenance, low-profit customers on auto-pilot–process orders but don’t pursue them or check up on them–and “fire” high-maintenance, high-profit customers by sending a memo detailing how a change in the business model requires a few new policies: how often and how to communicate, standardized pricing and order process, etc. Indicate that, for those clients whose needs are incompatible with these new policies, you are happy to introduce other providers. “But what if my largest customer consumes all of my time?” Recognize that 1) without time, you cannot scale your company (and, oftentimes, life) beyond that customer, and 2) people, even good people, will unknowingly abuse your time to the extent that you let them. Set good rules for all involved to minimize back-and-forth and meaningless communication.