In most of the cases when the person dies, his crypto would become useless if his family member do not know about his keys.
I do not usually tell my password or keys to anyone and i know majority of the people don't do this. We are being taught to keep the keys safe.
No one think that one day he will die and in that case, his family won't be able to use those savings (bitcoin/crypto) if they don't know the keys.
Also people won't like to share keys with siblings or wife because they can misuse them . So what could be the solution to this
Yes, they will never be moved again. You could make a will or leave a letter somewhere with instructions how to locate the seed keys if you like. Do not use the word keys, what you handle is seed words not private keys, never directly manipulate those as they could be easily stolen.
The whole point of using seed phrases is that you can write them with your own hands into a piece of paper, this is VERY intentional. A real private key is simply too hard to copy by hand, the temptation to use copy/paste or any electronic medium (including qrcode) opens a door for thieves. So the point is when you make a new wallet, you are told to write by hand those seed words, this is the only thing you need to protect, and optionally leave to your family in case you pass away.
Nothing else is important. No hardware devices, no passwords, no phones, only the seed words, this is how important those are, do not neglect them as they are your wallet, protect them and do not let them be captured by electronic devices of any kind. Incidentally that is also a cold wallet if you delete it from your device, that piece of paper with words written by hand, is the real cold wallet, not unplugged $100 gadgets, those have another purpose: Secure your HOT wallet.