Just calm down. Do you have Old 3DS or New 3DS? If your brother has Old 3DS and you have it too, then I think that we can solve your problem. Set up emunand on his 3DS, install freeShop on it and buy pirate FieldRunners DSi Ware (well, I've read that downgrade is pirating too so you shouldn't have any problems with that). Then update that emuNAND to 11.0 and do system transfer to your Old 3DS. You will have Fieldrunners on your 3DS and emuNAND on your brother's 3DS, and then you will be able to do DSi downgrade method, and then on your downgraded 3DS you will be able to restore your NAND backup.