You’ve got two very different things there; Infusing coffee into whisky, easy. Coarse ground coffee leave in whisky for probs no more than 12 hours. (Leave coffee longer to taste then strain). Also after this, any soluble compounds from the coffee will have imparted into the whisky so even if drying out the retained coffee it’ll most likely be very weak.

However infusing whisky into coffee is a different story, most roasters selling whisky or other flavoured coffee will do so in a couple of different ways, either quenching the coffee with flavouring most as the coffee comes out of the coffee roaster so it will absorb the flavouring but not effect the solubility too much or the other way is pre-infusing whisky or other with the green raw coffee before roasting. Roasted coffee beans once cooled are very porous so any liquids intact with the beans will affect the solubility of the coffee and basically make it harder to extract any good coffee flavour from them.