Bad news, folks.
In the past week or so I noticed that he was acting very lethargic. His last meal was last week and when I went to feed him yesterday it was obvious there was something wrong as he just seemed so weak when I picked him up.
Found him dead this morning.
Obviously it was something I did wrong, I should have taken my chances and let him go before it got too cold. After all that work into getting him back on his 'feet', he goes out like this.
The experience taught me a lot, though. Although I've only done it once, forcefeeding isn't so scary anymore and since I plan on keeping and breeding snakes for as long as I live, something tells me I will use the technique again in the future.
Thank you all again for your help.
RIP Chuck Norris.