That is exactly what i go through, for me atleast it has a “trigger” Anytime my father isnt in my life my stutter seems to just disappear but it comes back completely when he shows up again. And i mean to a point where im blocking every couple of words and one simple sentence takes 5 minutes to spit out, its horible Maybe she has some sort of “trigger” for her stutter? If she does it can definitly help (Stress could def be a reason for it to get worse as previously mentioned, this is just my take)