You can write down the seed words to the wallet that holds the coins and send them to separate lawyers/deposit boxes or to some other supports you think are suitable.
It would be a great idea for us to hold bitcoin for future children of yours so if i have given a chance i would love to hold for my children in the near future because we dont know what will happen in the future so thats the great idea, we should think our future and what will happen in the future, lets think our future so we must hold some bitcoin and save for our childrens future.