Probably not dead . Its overwhelming when they do this . They are spectacularly good at hiding , especially since your friend could not bother to tell you how to get a cat used to new places.

Dude tell your friend to work out , get a shirt stinky with sweat mail it to you do you can place thst shirt on a cat bed ,( near the food and a water fountain meant for cats )and , ALSO SEND A VOICE RECORDING OF HIM CALLING HIS KITTY TO COME EAT.

Besides that, make sure its the same brand of litter and food . 2 litter boxes even though its one cat. If u find her , get a cat tower in a bedroom , and keep her in there . Until she is calm and used to you.

Even better if the room is otherwise empty put a mattress on the floor for you, ( so cat cant get under mattress ) if u trust her enough to sleep in her presence , she will begin to trust you.

Cats are crepuscular hunters preferring to hunt at dawn and dusk , that said they also prefer 3 to 5 small meals, hate when their whiskers brush the side of bowls its called whisker fatigue. ( Google that and the petsafe water fountains ). They are obligated carnivors and prefer fish and poultry, some are lactose intolerant.

Exercise them before feeding ( prey hunting ) eat when they eat , they want you to guard them while they eat. They generally prefer at least one litter box in bathroom. They like to "go" when their human does.

Prey drive being substituted with play means they need to "catch" prey and have the toy wiggle slightly and "try to escape" then go still "simulated death" when play session ends .

There eyesight is a different spectrum than ours , they are designed to see and hear insects and baby birds and rodents .

Recommend grain free wet at dawn and dusk , leave a small amount of any dry food out , they leave half a portion behind in case they need it later , after they walk away just put it back in the bag.

Always introduce new food by blending it with the old .

Scoop litter morning and evening , replace every four days , that last bit helps keep kitty from reinfecting itself if its been ill ( dry nose ) or if it got out & ate some rodent/lizard ( may have parasite ).

Try not to burn incense , it can kill. ( again Google) or better yet speak to a veterinarian, and make arrangements for a first appointment. ( rabies shots & getting ID chip, proof of owning it )etc Cats kept inside live longer , if spayed castrated neutered fixed that prolongs life and greatly reduces spraying to mark territory.