Obviously not. If simply posting and participating on the forum was his priority, he would just do it with a newly created account. He doesn't need a Senior rank for that.
You are probably right, but it may worth mentioning that using an alternative account for posting outside meta would be considered as ban evasion and according to the forum rules, the alternative account will be banned if caught.
He can do this using other name and start fresh if he just want to continue posting. I agree on @Pawel on this one. The only downside for starting new account was he cant post images and post interval is long compared to his account limits when he is a senior rank. His account is a participants of long running signature campaign so theres a high chance that want to recover his account to regain his previous position campaign or to join on other existing campaign.