Apart from name recognition and the fact that he was both an Adams and president only a few years prior to becoming a Congressman, Adams did not receive that much of special treatment. You have to understand, the JQA presidency was largely a failure as his ambitious agenda was blocked at every turn by the Jacksonian congress. In all honesty, JQA had thought he would spent the remaining years of his life at home in Massachusetts out of the political fray just like his father had. His being chosen was seen more as an honorarium by his community, a way of giving thanks to the statesman for his service. He was elected to fill the vacant seat of a congressman who wanted to join the Church as a full time reverend. You have people using the language of special treatment to try and get Adams to accept the office, talking about "ennobling" Congress (Quotation from the Everett brothers, probably Edward, from Unger, John Quincy Adams, 261) with the expertise and experience of a former president, but it never translated into actual on-the-ground special treatment. Especially considering Adams turn towards abolition and acerbic opposition to the Manifest Destiny and Slave power expansionism of his successors, John Quincy Adams was seen far more as a nuisance and a troublemaker in Congress than as this enlightened former president. Hope this helps, let me know if you need anything else! :D