Odin sure is a very handsome boy. I'm so sorry to hear that he has cancer. So far I've had to put three of my cats to sleep. Like others have already said, you just need to look at their quality of life and when that's gone then it's time. Sometimes others will also let you know because you may not see what they see. I hope that he'll continue to remain comfortable and please give him some lovin's for me. My thoughts and prayers are with you during this difficult time. Please take care. (((HUGS)))