I more or less equate teaching someone about photography as being similar to teaching someone how to play guitar. There are multiple schools of thought but I can simplify them into two primary camps. 1) teach them about music theory and work that into playing songs, 2) teach them to play a few simple songs and then work music theory into the songs. Method 1 gets them to understand music and how the songs are put together but new students can quickly become bored and lose interest. Method 2 the student has no idea how the song is created or why they are using G, C, D as the primary chords in the song they are playing. However, over time the instructor can start talking about key signatures, sharps vs. flats, circle of fifths, etc.
OK photography, similar schools 1) teach them about elements of exposure, composition, color wheels, depth of field, diffraction, etc. 2) set the camera on "P" or "Auto" and let them start creating photographs and in reviewing the photos, work in the concepts of exposure, composition, etc.
Like with music, the really curious and motivated will stick with you in method 1 but many will lose interest. They just want to play a few songs around the campfire (take some photos) at first and as they progress, the finer details (music theory / exposure / composition) can be worked in.
Doesn't answer the original question but leads to my thinking on it. Since the OP already has the D7500, if it were my money I'd keep it and use it to teach the new student (son?) photography. I'd set the thing in "P" or "Auto" and go out taking photos with him. As they get experience in handling the equipment, they will soon start asking why their photo doesn't look like they thought it would. That is the open door to start talking about the finer elements of photography.
Just my 2 cents (OK, quarter) worth.