You are right, I don't think either that any investor will be happy, allowing his funds to just go like that after his death without pass it on to his next of kin . As at this stage of your life, you are suppose to have gotten someone which you can really trust to pass your inheritance and if you don't,it means you don't trust yourself either or you are not telling yourself the truth,no matter how distance or close you can be to your family members, there most be someone which you will trust and desire to be your next of kin, if you have not gotten your own family, which I believe that even among your husband/wife and children,you still have pick someone, for me I think, it is best you chose from your family, introduce and teach the person about Bitcoin,and assist him or her to also be investing in Bitcoin, so that he will be happy and do as you wish when you need his or her help in future(mainly health related issues) or after death, there will be no problems so that your instructions on your Bitcoin investment will be carried out properly.
Although the advice you said seems quite wise for everyone, you also have to understand that not everyone can like and be comfortable with such advice because everyone also has their own thoughts and tastes in giving certain things to others including those closest to them. Actually I also like the idea you said, but I don't completely burden my closest people to invest in something they don't like, so I prefer to give some choices and comparisons when they want to invest in something so they can judge for themselves that Bitcoin is indeed much better than anything else in this world.