Thanks, everyone for your kind replies.
I myself am doing and coping quite well. I work from home so close to my wife at most times. I also have a good network of friends and my work is very understanding.
For our days, my wife has no trouble getting out of bed to do a walk with the neighbour early in the morning, Pilates about mid-morning and visits friends for the days. So I assist by keeping her days busy.
She does Meals on Wheels volunteering two days a week.
The book we are reading is CBT for Dummies. We have a number of other books but this looks easy to get into and explains the thoughts-feelings-beliefs triangle as a start.
Also some good podcasts, 'The new psychology of depression' and 'Overcome depression and thrive'
The key thing is she feels extremely worthless and no good to anybody and sees not having a job as a failure. I stress, she does not need to work and that is why I volunteered her with MOW.
After I finish up work I make dinner because I love cooking, my wife loves eating :) We then either watch shows together, listen to podcasts together and generally talk a lot.
We will keep going and just keep busy. I will review all the suggestions so thanks everyone.