What will happen??
No one will have the BTC address. Hence will them isolated?
In FIAT, people can handover money to someone.. So, i predict BTC will be disappeared gradually.
Of course it will be gone if you don't give your passwords and addresses to your family. So the better thing to do is to make a copy of all your credentials, give them knowledge what bitcoin is, so that if you pass away at least they have the idea how withdraw it.