The man you think is Pope has not only resigned but confirmed his resignation and said speculation about it is absurd.
Yet you claim he is still Pope.
Clearly he is not THAT ill or insane because he has lasted another 6 years in retirement. Six years.
That strongly suggests to me that he has no will to be Pope and his will to resign in 2013 was free. It is hard to see what he would need to do to convince those who don't believe his resignation is valid.
There are people on this forum who think multiple space agencies around the world and hundreds of astronauts are covering up the fact that the world is flat. So, if it is any consolation to you, I think it is more likely that B16 is still Pope than that the world is flat.
Probability of 0.01 as opposed to probability of 0.