When I started out at about 14 I found a few programming books that really helped at my local library. It’s really tough to keep motivated as a kid, but if you give him tools and help him find joy in the process he’ll push himself to the finish line.
Good on you for supporting your kid, my parents told me to get off the computer and go outside every time they “caught” me programming.
Jquery is a swear word in professional front end contexts, the replacement is transpilation and dropping ie support.
Personally I used jquery up until react and babel got hot, now I never touch the dom directly with jquery and no longer have a need for the polyfill features as I rely on babel preset-env to support the browsers we have selected (especially for things like promises/async await/es6+ features)