It sounds as though it’s going well. My cats were far from this point until many months later. (We’re going on three years with one of them still resenting the fact that the newer one stays.)
There is definitely hope! Fingers crossed.
I think it has helped that there has been an adult in the house most of the time… H has just finished his 12 treatments of chemo so he has had a LOT of downtime, pondering the meaning of life- or as I see it- looking at his navel… 
and has been the ‘referee’ making sure they ‘play nice’. They have definitely progressed a lot faster than I thought they would. Let’s hope that by Christmas they will be sitting next to each other without hissing or slapping…
The hardest part is keeping older kitty away from the little kitty’s dry food. She has regressed and seems to think she should be eating baby kibble. 
I changed my icon to show our new kitty. The name given to her at the shelter was Regina, but she didn’t answer to that or Gina…but she does look your way when you call her Reggie. She is too adorable and velvety soft, just not into being held or sitting still for any period of time… Plus likes to sleep on hard surfaces, usually the corner under my treadle sewing machine… go figure.
What a cutie!!! Hope your husband is doing well and enjoying her company. 
^^Bunsen- yes H is doing better than expected. No vomiting during the treatment, thank goodness. To top it off, he is enrolled in college courses because he is changing jobs, so taking BIO101 after not having been in school for 30 years, plus chemo and then chemo brain? He is a trooper. Reggie has helped a lot- she keeps him from focusing or dwelling on bad thoughts. Just like a two year old child, when it gets really quiet in the house, you have to find out what she’s getting into…
Oh my goodness, Reggie is beautiful! Thank you so much for rescuing!
So cute. I bet your husband enjoys having the cats around. I am all admiration for his willingness to take on college classes at this point. I hope his recovery continues very nicely.