Sadly, it's no fun for leather that has been affected by alcohol consumption. Alcohol and petroleum distillates/solvents work away to erode the water based, leather PU protective surface, sometimes it can even mark permanently. It was designed for solvent based urethane topcoats used in some leathers before 1988. It accelerates leather age by removing the soft surface and may make it harder and brittle with prolonged use. Any stitching it comes in contact with can lose its colour as well.
One huge American 'car care' company uses this as an ingredient as it cleans and dries very quickly, however its cleaning power is not that smart when the leather loses its protective top coat and the cleaner then penetrates into the dye, allowing colour migration. So you frighteningly get the colour of your leather into your cleaning cloths as the top coat is gone! As you can imagine, it's all downhill from there. The only way to fix this is by a professional reapplying the dye and then the polyurethane surface back onto it, or just replacing the leather. Not a cheap exercise to fix.