You really tried with that cat. He may have something else painful going on. Also, full on tomcats sometimes have extreme hormonal swings for several weeks unless you get them a hormone shot, which usually helps. Also, for future reference, it is good to keep a cat contained and allow them to establish their base camp and then allow kitty introductions - cats are territorial, like little mountain lions, so your boy was acting all "Viking". His biting is a huge thing - a lesser person might have him killed. Bottom line - you have done alot for this cat, more than most, and you got him into a situation where he wont be suffering in the elements, miserable, hungry, afraid, possibly injured.
Thank you for the update.
Thank you for the update.