I agree with @lillycoyote tell him to take the bass back from wherever he got it from. If this is a bass from a lake, first off you will need at least a 200 gallon aquarium for this type of fish (in the end even that will be too small for it) because they are swimmers and grow very large real fast. They are also voracious eaters and a variety of live food (minnows, crickets, earthworms, brine shrimp) is best for it. Also when you have fish like this they produce a large bio load in the tank and so therefore the husbandry of the tank needs to be tops as well as one big heavy duty filtration system, and with fish like these a protein skimmer would come in handy although not necessarily needed for freshwater. Also be wary of putting live plants in the tank with these fish as you will be constantly aquascaping due to them uprooting them all the time. Invest in alot of rocks as fish tend to feel more secure when there are hiding place, caves and crevices that they can swim to if they feel threatened or scared or simply just want to sleep. Lastly don’t expect to put anything else in the tank that you don’t want to become dinner., this will inevitably become a species only tank. I have saltwater tanks now but I did start with freshwater years ago. I’ve seen people keep large mouth bass in an aquarium, but they are a commitment and not some “cool” fish to have just to have. They aren’t goldfish. So if you don’t have the tank size or are willing to invest in one I’d take it back, besides there are much better looking freshwater aquarium fish, maybe some African Cichlids they are colorful and quite the entertaining fish (pretty aggressive if that’s what he likes)
If he really is going to attempt to keep this fish and is serious about it as far as tank requirements and filtration go, join a feshwater aquarium forum there may be sections there with other people that have kept or are keeping american game fish that could lead him in the proper direction.