No offense, but this is yet another example of why I am glad that man is not in charge of my being forgiven or not.
If Jesus can say "Father, forgive them; for they know not what they do" to those who crucified him, I am severely constrained with whom I will pronounce damnation.
As far as him being baptized, if he has repented of his sins and accepts Jesus as being the son of God, who suffered, died, was buried, and rose again for the forgiveness of sins and for the promise of our being raised in the end, then I say, bring on the water.
As to the Pope baptizing him, that's between those two and God. I think it would make a profound statement...and there is precedent (you will, of course, recall, that the Pope baptized Magdi Allam, a prominent Muslim journalist, during the Easter Vigil back in 2008). I am absolutely confident that JPII would have gladly done so.