Was given gift card by patient family

Just to start this off, I did not want to accept it but the family member got extremely defensive and started waving their hands in my face about they are “NOT taking it back”. It was gifted last night. I plan on going in tomorrow on my day off and giving it to my manager. I guess my question would be what are the chances I get fired for being honest and giving them back. Not sure what to do. I do not want to lose my job over some gift cards.