I don't tell my family anything, isn't anyone's business but mine. They just know I do business software, and leave it at that.
One thing to point out, is it isn't necessarily family you worry about. It's the company your family keeps. Family is always proud when they think someone in their family is successful and they like to talk about that person to everyone.
Problem is, everyone has family members who hang out with bad people who get jealous and will do anything from reporting you to the IRS, to robbing your house. This actually happened to my father before I was born. He had a good job at the time, my aunt tells some of her shady friends how well her brother-in-law is doing, and her friends ambush him one night when he's taking out the trash. She had no idea her friends would do that, she just thought she was saying nice things about her brother-in-law.
That was just for having a full-time job as a mechanic, and working a lot of overtime. Not even rich or privileged. Just a few good paychecks is enough to motivate people to come rob you at gunpoint in your own home.