My first cocker spaniel I bought from a breeder who held in to him slightly linger because he was better behaved in the ring than his brother (who she ultimately kept fir show and breeding) mainly because she was editing to see if his colouring changed, which it did not (white mark). So we were lucky to have a perfectly trained puppy - house broken, walk in a lead very well, lots of commands, grew up in the house with a cat etc.
I’d visited the vet to talk about dog breeds before buying our cocker spaniel. Many of our requirements were similar to your mother.
There were a number of small to medium dogs the vet recommended. He suggested looking at the kennel club to find reputable breeder and to look at their list of questions on their website to further weed out any problems. Our first cocker lived to 12 and never had any health issues until his stroke.
Our vet suggested when he was 6 to think about a second dog. We have a lovely cocker who is now turning 10. Our cat died from old age a few years ago but he’s still ok around cats. The lady who we use for home boarding when we go away has a cat. They’re great at sitting in the same sofa together and ignoring one another.
Other breeds the vet suggested were Bichon frise, cavalier King Charles spaniel, Shih tzu. We were advised to steer clear of terriers as often, in his experience, they go after cats. (I’m sure there are many that don’t - this was advice given to us).
