If the child seems to be using repetitive language because he is anxious or worried, set aside time to talk about his concerns…Come up with a reassuring phrase that addresses his concern, such as, “That’s only make-believe. It’s not real.”
Crissey, Pat (2013-12-02). Teaching Communication Skills to Children with Autism (Kindle Locations 2094-2095). Attainment Company, Inc.. Kindle Edition.
Basically tell the kid that what they are afraid of or anxious about isn’t real, it’s just fake. That’s a great way to calm down anxiety (read that with a voice saturated in sarcasm). You don’t downplay something that causes someone anxiety. You talk to them about it and recognize that it is something that causes them anxiety, not ignore it or downplay it. This is some seriously terrible advice.