There are a lot of posts on this forum about how we should protect our assets and not to share our private key and seed phrase with anyone, not even our loved ones. Even when I read about these things online, I always read that our seed is meant to be kept private, which leads me to have the same thought as you.
Are people really aware of unforeseen circumstances? What if something happens to you? Who will be able to handle your assets when you're no longer there?
I understand that every investor has a different motivation for investing, but I think the majority have been investing in Bitcoin in order to improve their family's situation. If you invest patiently for a long time and make significant profits while keeping your personal information private, and any unforseen circumstances occurred, then all of your hard work will been in vain leaving your family members with nothing IMO.
There is no way that every member of your family will turn to be your enemy, they must be someone you can trust to keep your secrets, such as your parents, son, or siblings. You don't have to tell them about your seeds, but you should tell them about your holding and, if you reap any profits make sure to show them love because that's the only way they can take their eyes off from the information you shared to them. If you try to be greedy, they will lose patience and begin to think negatively.