SOLVED!
Hi there everyone, back in 2017 I gifted my brother dogecoin, and he found his 12 word phrase backup. But that's the only thing I wrote down. I downloaded the local BIP 39 private key generator that can reverse a mnemonic, but I cant seem to import this into doge core or multidoge. I think I'm doing this wrong, can anyone help out? I'm a software engineer, so you can throw me any tooling or jargon, I just don't understand which of these pieces of info converted from bip39 is the private key data I should use in a wallet or key file.
The Solution:
The 12 word passphrase was used on the since removed iOS app doughwallet. On their website there is a mnemonic recovery tool. It is a modified version of the standalone BIP39 generator. The first address and private key it generated after entering was the correct one.
Check out their website here: https://www.doughwallet.net/{:rel="nofollow"}
Here is a direct link that is still up for the recovery tool: https://www.doughwallet.net/doughwallet-recovery.html.zip
If either of these links do not work in the future, please try to contact me to get the files. I will keep them archived for anyone who needs them (but you shouldn't ever trust someone hosting a tool like that other than the creator! Any web page can steal your info.). If you use the tool, I do recommend turning your internet off and going into incognito. Then generate your key, save it securely and lock it. Then back it up to a cloud storage provider, and write down any passwords of course. I hope this helps!