I haven't set up a winch on a truck, but I've wondered about fusing them too. I did a little poking around and it looks like there's some debate as to the "right" way to do it. Some people just run it straight to the battery (like the starter, which isn't fused either) and call it good. It's simple, and simple is good, but it means you're gonna have a bad time if the cable rubs through or gets pinched in an accident. The risk of it shorting out can be mitigated with careful routing, but you also don't have an easy way to kill power to the winch if something goes wrong, which strikes me as sketchy. Some people run a manual shutoff switch or a relay between the cable and the battery. You can also get circuit breakers that these guys seem to like, which can be turned on and off manually but also click off if overloaded. The breaker seems like a great idea to me, provided it's properly sized so that it won't click off during normal use, and provided it can handle life in the engine bay. One commenter raised the concern of what happens if you're in a sketchy situation off-road and your breaker trips and leaves you hanging, which could be a reason to go for the basic switch over the breaker, depending on how hard your mom intends to send it.
+1 for the voltmeter, that should give you a better idea of what you're up against.