You need to explain in detail what went wrong, I don't have first hand experience with BSD android wallet but it also works like the normal desktop wallet when it comes to wallet recovery and backup.
I understand that he had a Coinomi Wallet, but this is not the official development of the BSD team, but a third-party wallet with a huge amount of cryptocurrency supported.
Therefore, the developers of the Coinomi Wallet can help most quickly
https://t.me/coinomi_official.
I always didnt trust such wallets, especially the dekstop Coinomi was hacked in late February, the problem was in spelling of seed phrases.
Are you sure he is talking about coinomi??
I think he is talking about bitsend android wallet, nothing related to coinomi.... If you just read the first page of this topic you will also find a guide on how to recover private keys from bsd android wallet.
Anyhow coinomi is a not perfect but nice wallet.
For long holds, one must try to backup private keys instead of wallet backups because you never know until when the wallet will be supported. I do this for all my coins: Bitcoin, Ethereum, Bitsend, others.