True to life Illustration of three humans: old woman, younger woman and man

I'm an author and would like one of the scenes from my latest book to be illustrated and/or painted. It requires true to life illustration. I have the image of the old woman as a licensed image but i wanted an illustration of her. The woman behind her, with one hand on her shoulder should be in her twenties, an Australian WW1 nurse. On the other side of the old woman would be a WW1 medical officer, also with his hand on her shoulder.