It is not an appropriate place given the time sensitive nature of the request. The account has been secured though but it is a highly disputed account so recovery may be tricky for you Clan mate.
All Inactive Clan Leader change requests need to be actioned through the relevant thread in the Clan Central area of the forums. There are strict criteria for changes in leadership though including the Inactive Clan Leader having not logged into game for 12 months or more before a change can be considered normally.