Have your considered getting another cat? If Bomber and Tabitha were long time house mates, then she might be feeling lonely. I did that when I had to put Sparkey down at age 13. I waited about 6-8 weeks to make sure that Silk undersood that Sparkey wasn't coming back then got a 1-1/2 year old rescue named Crush. The 2 cats never really did bond in the way that Silk and Sparkey did, but I firmly beleive that Crush's company kept Silk alive for another 4 years. (Silk had thyroid problems and couldn't be medicated, she fought too much.)
If you're green, you're growing...if you're ripe, you're rotting!
I try to greet the world like my pets do...boundless enthusiasm, intense curiosity and no concept of yesterday and tomorrow.