It’s not really about that, though, is it? It’s about what colleges he wants to apply to and what they want to see. Have you researched what the schools on his list ask for?
My D22 ended up doubling up on English this year and is taking AP Lang online and AP Lit. Her school doesn’t offer AP Lang so she couldn’t take it last year and took English III honors. She is an English/writing nerd, though, and wants the APs for some of the schools she’s looking at.
If he is more STEM oriented or not applying to top 20 schools it’s probably fine. A lot of seniors take it a little easier in their schedule. My D22 is not looking at top 20s and I think almost all of the schools she’s looking at would be fine with no English senior year since he has other English courses over the summer and the Great Books course.
If he’s looking at Top 20 schools or very selective schools they may want to see rigor (aka AP Lit).