No need to update to 10.3, afaik. He's in a franken-firmware, and whatever titles are used for the browser and to open game cartridges are likely incompatible with his current NATIVE_FIRM. He could go to 10.3 and downgrade again, but it's possible to just flash all the .cia's on top of the current ones through sysUpdater/SafeSysUpdater.
Now, he said he can't use the browser, so browserhax isn't an option. Game cartridges can't be launched, so no oot3dhax or ninjhax. Ironfall on the eShop is updated, does the method to get Ironfall 1.0 still work? If he got an incomplete flash, either the browser is still 9.8's(meaning he's in 9.0 FIRM) or the browser is 9.2(meaning he's in 9.8). menuhax, if installed, should still work if the latter is true, afaik. If there's no entrypoint... sucks to be his 3DS.