It is very normal to be afraid of telling family members about your investments to avoid it being stolen which might lead to a family feud but then it is okay to let them have an idea of what you do and how you save your source of income. You don't necessarily have to give them the entire details just an idea. Also documentation also matters, in as much as you don't want anyone to know how much you have while you are alive, you definitely want them to have a share each incase unforseen circumstances occur, so document every little detail as much as you can.