I forgot you can use cart for JKSM although he still need to have a homebrew otherwise he wont be able to use JKSM considering he doesnt have gateway / sky / lumacart is fine. u can still extract extdata from sd card in jksv. my jpn copy is physical, usa is digital,
--------------------- MERGED ---------------------------
you dont need to buy it from eshop, depending on what version your 3ds is you might be able to use it, you might want to give this a read after checking what version you have on your 3ds, you can do so by checking the system settingsim still probably gonna need a tutorial or something to understand what exactly to put where
or maybe im just stupid
although if you really need help, I suggest you look around on the forum instead of typing it on this post where it's suppose to be about MH Stories lol
https://3ds.guide/