I’ve made an edit of the Clone Wars which covers the key moments from 2003 CW, 2008 CW, and Forces of Destiny. It also includes the key moments from Tales of the Jedi - essentially the full clone wars era timeline.
One of my recommended viewing paths there is “I ONLY want to watch content that sets me up for the Filoniverse shows quickest”. That one sounds like what you’re after in terms of explaining Ahsoka, Maul, Darksaber, etc.
Read more here: https://originaltrilogy.com/topic/The-Clone-Wars-Refocused-COMPLETE-Subtitles-for-season-one/id/80467/page/99#1599231
Reviews are here if you want to get more of a sense for whether or not this’ll be interesting to you and your son. https://fanedit.org/clone-wars-refocused-the/#reviewsTab
PM me if you’d like to request that.