I see you're in Australia. If your buddy just picked up a large local spider, it's probably a Selenocosmia species of tarantula. If that's the case, let him know that they have pretty potent venom for a tarantula and don't make it a habit of feeding live vertebrate prey to them very often. It's OK every now and then, but live vertebrates have far too high of a calcium content when fed on a regular basis and can definitely cause problems when the spider molts (wet molts, etc). Not to mention, vertebrate prey like mice can injure or even kill a spider. He's much better off just feeding larger invertebrate prey.