I remember this movie I watched back in the 80’s or early 90’a I think it was. A couple bumps into a little girl in a park who is looking at Castle statue that’s in the park. The little girl is into Camelot and King Arthur. So is the husband who i believe his name was Bill. He becomes attached to the little girl and the couple adopts her . The little girl bonds with Bill over the Camelot , but not so much with the wife. He dies suddenly and the adopted girl refuses to believe he is gone pretending to have hot chocolate and coco with Bill every night. When the wife makes her understand that Bill is gone she demands to go back to the children’s home. I believe they do bond buy the end of movie and she goes back home with the wife now her new mother. Does everyone remember the title of this movie ?
I think it is the 1984 movie remake of Sentimental Journey. There is little information about it on the IMDb, but the TCM plot summary, brief as it is, suggests it does a gender switch on the original 1946 plot where the child bonds with the mother instead of the father and the mother dies. Your description got my attention because the father in the 1946 version was named Bill, but that is not his name in the credits for the remake. If you can find a way to watch it I’m pretty sure you’ll find that’s it.