Kid peed on our couch

Nephew and his friend stayed over a few days ago and slept on the couch. We haven’t been home much since he left and only found out just now that two of our (giant brand-new sectional) cushions are soaked with piss as well as four throw pillows and a few blankets. The covers come off but underneath is an absorbent memory foam type of thing. How would we go about cleaning this?