Like every other investment such as real estate, stocks and other forms of investment we know that you can invest in that kind of things and then you get something like say a Certificate or a Binding Document as a proof that you are part of that investment, now that of bitcoin all you have is just your address, your password, key and seeds as proof of the ownership of the wallet.
BTCSo now if one is considering buying bitcoins and saving for his/her children in the future is there any way to do that with bitcoins apart from having to write down your details somewhere. I'm asking because with that kind of stuff if no one knows your seeds or password no one can get the coins.

It is good to invest for the future of your children especially if you invested it in bitcoin. There has a humor that bitcoin will end and you cannot say when and how it will end. But as a positive thinker I don't believe that btc will end so I will continue to invest and hold my btc for my future. And if you do it now, you are assure that the life of your children is good.