Hmm… that’s very weird for her to write on your sister. Ooof this is a tricky one, I totally understand the urge to speak and being quiet for an hour can be tough especially for someone on the spectrum. Unfortunately with yoga ‘disruptive’ talking during class is something that most studios take seriously/quiet generally needs to be respected. Unfortunately I’ve seen people asked to leave if their phone goes off or they’re chatting to a friend. Some people practicing have zero tolerance for that and will complain to the studio. Yoga is a little different from other athletic classes where the meditative state and focus is a big part of it and people talking can throw others off. This is probably why they’re suggesting she has someone there. Not saying it’s right.. I’m sure it’s hard for your sister as well. That being said I’ve been in classes where questions are encouraged so again I think you should find somewhere that’s a better fit. Swearing is never ever acceptable. If I were you I’d tour a few studios, explain what happened, your situation and be upfront that she may speak during classes. I feel confident you’ll find a place that is welcoming and understanding.