Guilt Tripping Boss?

Do you think it's ok, as a boss or even a manger, to guilt trip employees? My current boss - which is also my husband's great uncle - tells me all the time he doesn't trust anyone else to do my position, guilt trips me if I'm even one minute late and then gets super angry if I tell my family anything that happens at work. On top of this, he tells my husband's grandma everything and she blows up at me for no reason. I just found out that I'm in line to inherit the company and I want nothing to do with it. Now, I'm getting guilt tripped because I'm wanting to find another job. I got told "it's not fair because he employed me and that I should take over so he can retire". My family, except my parents, know I'm over this and want to move on with another job. I'm not the kind of person to run a company, and nor do I want to spend my life running a manufacturing company. I just don't know how to move on without building bridges...