Family Financial Planning

I am in the financial services sector, and have done this on my own full-time for 1 year but have had internships and other work experience in this sector since 2002. The father of my wife has a financial planning practice success that it is willing to sell to me slowly. There are currently about 800 families with whom he worked with a lot of 401 (k) and health insurance he manages. He just wants to work with its top 50 customers who leave a lot of customers that service and I could work with. In other words, an immediate clientele, the more I'll have 20% of any company, produces, to make sure I stay around. This double my income next year and more than double in the coming years. I am good at what I do, but having already an established customer base would be huge for my career. My concern is living near family and have potential problems on the road with him and having a grave. Advice?

All reservations can be solved in a contractual agreement. This is what they are for.

Foresee all possible problems in the future and write a contract that protects you both if they occur.