Has she had the stomach problems checked by the GP to check there's nothing physical going on? The GP could also prescribe anti anxiety medication or refer her to counselling. It sounds as if several losses (husband, dog, man friend and retiring) have compounded to bring her down. In my case I was so busy with work and family after losing my husband and now retired and living on my own I think of DH much more. However, I'm happy living on my own.
Would volunteering keep her busy and possibly help her.
Re painting metal bistro garden set