When this mom is upset with her SIL, she asks Reddit:
My son is five and autistic. Sleep has always been a huge issue for us. Its partially what led to my divorce - thats how severe.
He still uses a pacifier to soothe at night and sleeps in my bed. I have, in the past, tried every sleep training method possible. I've had him on every med. I've weaned him off his pacifier and put him in his own bed. Paid five seperate sleep consultants. Absolutely nothing works.
In a fit of exhaustion I went full extinction - took the paci and left him in his room. He didn't sleep at all that night, I kept him awake during the day, and he then didn't sleep at all the second night. He was exhausted and it took me months to rebuild his trust in me after the fact.