What do you do at bedtime?

Last Thursday, we hosted our homeschool play day that has carried on since last year's Wolf Camp that we hosted on our property. Only Kyle could make it last week, and after I returned from taking Kyle home, Sean was on the computer. It was nearly 4 p.m. and I told him we needed to do some school. I asked him to turn off the screen.
He told me he had done science the night before, but I was skeptical. I hadn't seen him doing science the night before.
He showed me a video he watched about opioids. I decided it was indeed science, and pretty advanced stuff, so I asked him to get his science composition book and carefully, in his best 7th grade handwriting, outline what he had learned from the video.
He first was surprised that he is in 7th grade. I guess he forgot. I have never made a big deal about grade levels, but I like him to know what level he is now, because we are getting ever closer to high school.
He pulled out his sketch pad, held it up and asked, "You mean like this? Can you read this?"
He was seriously curious if he had done work at a 7th grade level. He had outlined what he learned. And he had obviously paused the video to take careful notes and to be sure he had spelled the words correctly before moving on. It was well organized, neatly written, some information was circled with a mark that denoted a this and then that type of scenario of how pain is communicated in the brain. It was so impressive that I was left speechless.
Mostly because we haven't even talked much about my expectations for this year, or about how to take notes, and how to be thorough. But also because the subject matter was very advanced and complex, and he had done it late the night before, when he could have chosen anything at all to do. Legos, a movie, any number of things.
I didn't want to skip doing school, so I encouraged him to think of some reasons why a Dr. would prescribe an opiate. He had some of the medicines listed, and said maybe morphine for a broken bone.
He searched broken bones, and the various ways a bone breaks. I asked him to sketch those and label them, and he did it with skill.
His work led me to wonder if he knew some of the clearly advanced biological terms, and if he knew what the person meant when talking about enzymes. He hasn't chosen to do that work yet, but I am sure he will soon.
And I wonder if we all, after at least some exposure to watching others categorize information, come to understand how to take notes and outline information?
I also wonder if he would do better to start school at 4 p.m., because he clearly does some of his best work after I'm in bed.