this manga implies that it's okay with not having any dream and support someone else's. you dont have to force yourself to have a dream. you will eventually know what you want to do. and sometimes it is to support someone you love.
this is accurate depictions of magic legacy. if your granpa have magic when he died, the magic didnt die with him, it gets inherited by some of his descendant. if the descendant refuse they will got ill. the magic itself is actually most of the time demons.