[MunchkinMan]

"Usable once only," for all intents and purposes, should only matter with respect to Items. Though some non-Item cards do say it, they are the exception, not the rule. Regardless, neither of those cards are Items, so a lack of "usable once only" has nothing to do with how these cards are to be treated. Also, any card type that the rules do not explicitly say that it stays in play (e.g., Classes, Items), should be discarded once its effect is over. Friendly is the kind of card that its effect is done when combat is over, so it gets discarded. Same with Dead. If your father wants to argue this, you could say that these cards are Monster Enhancers, and the rules specifically say that you should discard the Monster(s), Monster Enhancers, and one-shot Items after combat is over.