My first challenge hopefully I have got this right.
Firstly check levels and adjust.
clone stamp to build jacket and recreate background tones.
Faces and hands using clone and paint brush.
Kept father and childs original features as much as possible.
Decided child was wearing dungaree type trousers and most likely a checked shirt and built them up from scratch.
Father appears to have a collarless shirt and dungaree front under a black jacket. Is it a millitary Jacket?
Cloned right of bench back for left hand side.
Having built the background as a painting effect, rebuilt the textures overall using the patch tool to give it more authenticity.
Lastly overlay layer and multiply to achieve some depth to the shading.