My dearest Jenny lived until she was at least 20, but was one of those cats that got old quickly and stayed there - she had an operation for skin cancer at the age of about 10, and really slowed down after that. Really, I had been expecting that the time could come at any time for the 2-3 years before I actually lost her. She became a little arthritic, otherwise in good health until her last year, when she did get really frail, and had to have regular warm baths as she couldn't wash so well - she ate well right up to the last day or so and never had a single 'accident', even though she was getting a bit senile. I kept reminding myself that she didn't know - cats don't have the fear for the future that we have for them.
Try to enjoy the time you have left without anxiety - as Licky isn't anxious and will be happy as long as he's feeling well and as he continues to be so much loved.