I really like that you try to connect with him that way. It's so nice when people do. Some of my neighbours used to 'use' me to bridge the gaps to their kids because I 'speak' fluent lego and am fandom savvy-ish. (Depending on fandom, but I'm fluent in Marvel and much of DC, too.) Apparently they get awarded extra 'points' just for knowing people who can argue coherently about the various X-mens' powers... 😆

I'd really recommend mecabricks to your grandson. For one thing, it's a lot cheaper than physical sets (free!) and a great way to plan for and design future builds. For another, it's useful to learn how to employ CAD programmes. (And unlike fluency in lego or super heroes, that's actually a marketable skill... 😉) If he doesn't have experience with that, I've made a tutorial for using mecabricks and posted it here, which might be of interest. (You can download the pics in order (just right click on them and save to your computer) and just use it like that. There's no need to use this site, nor does it identify this site, deliberately. Separation of church and state and all that...)