The cover of the book doesn’t sell the story, which now you’ve explained it, sounds really interesting and is something I’d like to read.
However, as I’m not familiar with ‘hospital blues’ or ANZAC the cover wouldn’t make me want to pick the book up.
I looked up what ANZAC is and rightly or wrongly, it’s not something that I’ve ever heard about in the UK.
The picture used on the cover has a lovely story behind it but would be better placed on the inside back cover which a reader would appreciate after they’ve read your book.
I don’t mind the title but the subhead makes no sense to me and as others have said, it all feels very Mills and Boon-ish, which I’m not interested in. Personally, I don’t think you should need a subhead on the cover to explain the story. The ‘true story’ line is enough.
It would make sense to make the cover the ‘hospital blues’ colour and use imagery that shows when and where the story is set (Australia? 1940s?).
The cover doesn’t reflect anything that you’ve said the book is about. I’m sure a publisher/ graphic designer could help you. As it stands it looks like you’ve created a lovely memoir for your family and you should be very proud of that. A more dynamic cover could open it up to an external market.