But with this account, he can only write in the META section.
It seems that neither you nor your friend has read all the rules of this forum. Sometimes ignorance of the rules can play against you.
He told me that he tried to write from this account to any section and nowhere does it work

A little correction for clarity, a banned user can only post in their appeal thread in Meta, any post outside that thread; even though it is made in Meta would still count as ban evasion.
thank you for confirming my statement
[moderator's note: consecutive posts merged]