Esther Rolle's absence explained in the episode "The Enlistment" that she was at a funeral

But the absence of John Amos in the episode " The Baby" wasn't explained at all. It was almost like he wasn't no longer on the show. Nothng was ever said about him visiting relatives or anything. I think it's kind of weird that none of the characters would not mention the James character in the entire episode. What was wrong with these writers?