What aid and comfort did he give the enemy?
Its all in the link below. His disgusting behavior continues in the Senate. Please note his behavior during the Senate's MIA/POW hearings:
McCain stood out because he always showed up for the committee hearings where witnesses were going to talk about specific pieces of evidence. He would belittle and berate these witnesses, questioning their patriotism and otherwise scoffing at their credibility. All of this is on record in the National Archives.
The War Secrets Sen. John McCain Hides (VERY long but VERY Damning)