Completing (like extrapolating) a picture of a person

Hi :) First: I actually don't know if what I'm trying is even possible. It seems doable to me, but I'm very far from being an expert. That is also why I'm here. So I have an old (about 7 years maybe) picture of two people sitting on a beach. I had to scan a print since the original is lost, which means it's not the best quality (also there was a lot of sunlight when the picture was taken. One person is an adult, the other person a little child. Both are, accordingly to the stay at the beach, mostly naked. The child is sitting on the lap of the adult. Most of the adults face, legs and the right part of the body is visible. The rest is hid by the sitting child. What I want to have done is to cut the child out of the picture and to fill in the gap as realistic as possible. To kinda enhance the picture as whole would be great too. I am aware that it is not possible to do magic via image editing. But since moste of the person is visible, at least more than 50 % of each part, I'd think it may be possible, through copying the visible parts and being realistically creative . At least for experts. Since it is a rather private family picture, I don't want to post it immediately here. I hope a first assessment of my issue is possible nevertheless. Oh and also I'm really not sure about a fair price, since I am not even sure that it's possible to do it. So I'm very open for discussion concerning that matter. Greetings!