Thank you for story.
My son diagnosed with autism at age two. Now he is 7, and practically did't speak (not counting simple phrases like 'give water, give pasta' etc..).
Sorry for disturbing, but could you tell me (if it OK for you) at what age you sister start to understand / talk, and is there some 'aha!' moment maybe? And did you mom works only with ABA or some other method too?
Sorry about my english.