Your brother needs to submit a ban dispute regarding his ban for being flagged as your 'alt account', explaining in detail the situation, if you two use the same PC to avoid this in the future if one of you is banned its not a great idea for the other to play.
Yes, you can create either a ban apology, or a ban dispute in the Punishment Appeals sub-forum. In this case, I would recommend an apology, explaining what happened, or dispute the ban, saying that you have a brother with a 2nd account.
I have already been banned several times and I have already explained, and so far we have always been banned my brother, we have 2 accounts on the same pc because
we have one pc
I guess you have to contact a higher-ranked admin, or even an owner to get around this, if its even possible. You can try it on the PH teamspeak ip: perpheads.com, the PH discord or I resolved a similar case once, by contacting them in game, using f6, when they were on.
Your brother needs to submit a ban dispute regarding his ban for being flagged as your 'alt account', explaining in detail the situation, if you two use the same PC to avoid this in the future if one of you is banned its not a great idea for the other to play.