Profound autism and Seroquel

Hello, my daughter, 50,nonverbal, profound autistic, epileptic has been on Seroquel for 12 years, usually around 75 a. m. and 100 pm but due to a borderline EKG with qt prolongation , found in hospital 2024 during 49 day stay for gi issues, sigmoidectomy and long recovery, neurologist wants her to titrate off so just started reducing 75 to 50 mg am dose, leaving 100 mg pm alone but in a week her affect has changed, more subdued ,taking a long time to feed herself, used to inhale food, and seems lethargic, disinterested in her usual routine activities
Wondering if anyone has tried to get their child off Seroquel and how it was?
Thank you Lisa's mom