Living science suggestions for 13yo special needs child

My son is 13 & mildly autistic (will turn 14 this summer). He is at least a few years behind what would be 7th grade for a neuro-typical child. I have decided that his 12yo sister (going into 7th) is ready for Apologia General Science, so I will teach them science separately this coming year.

We have been using living science books for the past two years and just finished studying fossils, geology, volcanos, and earthquakes. Some of that was “over his head” a bit (i.e., The Geology Book, published by Master Books), but he definitely didn’t take too well to the Exploring Creation with…. series.

He seems to do well with books at about a 4th or 5th grade level, especially if the harder ones are read to him. I asked him what he would like to focus on for science next year, and he said he would like to study more about animals and insects (“like, what their bodies are like and stuff like that….”), and he also mentioned doing some things outdoors. His lessons definitely need to be short.

I am looking for suggestions of living science books for him. I don’t know anything about some of the SCM recommended books such as the Burgess Animal Book, and I’m afraid I’ll end up choosing things that seem too babyish for him. Even though he mostly functions emotionally and mentally at perhaps the level of an 8- to 10-year old, he is often well aware of writing that is aimed at a younger child.

I’m wondering if I can adapt some books such as Burgess by just not using the cutesy names like Jenny Wren and Buster Bear, or would the stories still be to young for him? Two years ago, we did read Eugenie Clark’s biography, Shark Lady, and he seemed to enjoy that, but I think we would still want to supplement something like that with more information about the particular animal. I’m also thinking that he has likely forgotten much of the basic stuff we learned four or five years ago about which animals are mammals, amphibians, reptiles, etc.

Any ideas? Thanks.